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Open access

M. Saternus, T. Merder and J. Pieprzyca

URO-200 reactor belongs to batch reactors used in refining process of aluminium and its alloys in polish foundries. The appropriate level of hydrogen removal from liquid aluminium can be obtained when the mixing of inert gas bubbles with liquid metal is uniform. Thus, the important role is played by the following parameters: flow rate of refining gas, geometry of the impeller, rotary impeller speed.

The article presents the results of research conducted on physical model of URO-200 reactor. The NaCl tracer was introduced to water (modelling liquid aluminium) and then the conductivity was measured. Basing on the obtained results the Residence Time Distribution (RTD) curves were determined. The measurements were carried out for two different rotary impellers, flow rate equaled 5, 10, 15 and 20 dm3/min and rotary impeller speed from 250 to 400 rpm every 50 rpm.

Open access

T. Merder, M. Saternus and P. Warzecha

Abstract

Both primary and secondary aluminium have to be refined, especially by barbotage process. To know better the mechanism of blowing argon through aluminium in reactors with rotary impellers, numerical modelling is applied. It allows to obtain useful information like: the level of velocity field or participation of gaseous phase. However, numerical analysis requires choosing the proper model which would describe the physical phenomena occurring in the process. So, AnsysFluent code was used in the research. It allows to calculate the two-phase liquid flow for the 2D and 3D co-ordinate systems. Results of calculations for the 3D case can describe more accurately the spatial picture of the movement trajectory of the blown gas bubbles. Calculations were done for the flow rate of refining gas equal 5 dm3/min and for two cases: when there was no rotation and with 300 rpm rotary impeller speed.

Open access

W. Piekarska, M. Kubiak and Z. Saternus

This work concerns numerical modelling of thermal and structural strain, resulting in heating and cooling of laser butt-welded joints. Numerical analysis of strain is carried out in Abaqus FEA. Through the use of additional author’s subroutines, the structural strain caused by phase transformations during heating and cooling of welded elements is taken into account in the analysis. V.I. Machnienko models as well as Continuous Heating Transformation (CHT) and Continuous Cooling Transformation (CCT) diagrams for S355 steel are implemented into UEXPAN subroutine in order to determine the kinetics of phase transformation in the solid state. The model takes into account thermomechanical properties of the base material varying with temperature.

The paper presents results of numerical simulation of temperature field, predicted structural composition, thermal and structural strain in laser butt-welded joints.

Open access

W. Piekarska, M. Kubiak and Z. Saternus

Abstract

Numerical simulation of deformations in laser welded T-joint is carried out in this study. The analysis is performed using Abaqus FEA engineering software. Additional author’s numerical subroutines, written in FORTRAN programming language are used in computer simulations where models of the distribution of movable laser beam heat source, kinetics of phase transformations in solid state as well as thermal and structural strain are implemented. Thermomechanical properties of welded material changing with temperature are taken into account in the analysis. Presented results of numerical simulations performed for the laser beam welding of two perpendicularly arranged sheets include temperature distribution, kinetics of phase transformations in solid state, thermal and structural strain as well as estimated welding deformations.

Open access

M. Saternus, A. Fornalczyk and J. Cebulski

Abstract

At present, every launched car must be equipped with a catalytic converter, in which the precious metals such as platinum, palladium and rhodium play catalytic role. Catalytic converters have a limited life time, therefore they have to be replaced and become a valuable source of platinum group metals (PGM). Currently in the world, used auto catalytic converters are processed in pyrometallurgical or hydrometallurgical way. However, the first step of such treatment should be a chemical analysis. In the paper catalytic carriers were analysed taking into account the level of platinum. Scanning electron microscope was used. The analysis concentrated on testing samples coming from different catalytic carriers. The structure of tested samples, chemical analysis and X-ray energy spectra (EDS) where presented as well as the discussion of obtained results and possible methods of platinum recovery.

Open access

W. Piekarska, M. Kubiak, Z. Saternus and K. Rek

Abstract

This study concerns numerical modelling and computer simulation of thermomechanical phenomena accompanying spiral welding of pipes made of stainless steel X5CrNi18-10 using a laser beam. Based on Abaqus FEA software, 3D numerical analysis was performed. Power distribution of spirally moving heat source was implemented into additional DFLUX subroutine, written in Fortran programming language. Thermomechanical properties of steel changing with temperature were taken into account in the analysis. The efficiency of material melting by different welding sources as well as the influence of heat load on the shape of melted zone, deformation of welded pipe and residual stress were examined.

Open access

J. Pieprzyca, T. Merder and M. Saternus

The way and speed of steel flux flowing into mould of continuous casting (CC) machine belong to the important parameters characterizing the steel continuous casting process. Such flux causes determined kinds of steel circulation, which together with simultaneous steel crystallization influence the creation of ingots primary structure and quality of its surface.

The article presents the results of modelling research which aim was to determine the optimal location of submerged entry nozzle in square moulds (130 x 130 mm and 160 x 160 mm) of CC machine. Such a research was carried out for two different grades of steel (low-carbon steel and high-carbon steel), which feature different parameters of casting.

Open access

J. Pieprzyca, T. Merder, M. Saternus and H. Kania

Abstract

The article presents the results of research concerning the change of liquid steel flow and mixing in the T-type tundish. It has been installed in one of polish steel plants. Continuously changing market conditions have forced the change in the range of cast strand. As a consequence the new control system of liquid steel flow had to be applied. Up to now a baffle with notch has played the role of steel flow regulation. It was placed between the inlet and channel zones of a tundish. However such solution was not satisfactory. Therefore, a new flow control equipment was designed - baffles and different constructional variants of turbulence inhibitors. To estimate the efficiency of their functioning and in the same time their influence on the tundish work, modelling research was carried out. The research was also complemented by numerical simulations. The article presents results of such research as well as experimentally and numerically determined RTD curves of mixing (Residence Time Distribution).

Open access

M. Kubiak, W. Piekarska, S. Stano and Z. Saternus

Abstract

The numerical model of thermal and structural phenomena is developed for the analysis of Yb:YAG laser welding process with the motion of the liquid material in the welding pool taken into account. Temperature field and melted material velocity field in the fusion zone are obtained from the numerical solution of continuum mechanics equations using Chorin projection method and finite volume method. Phase transformations in solid state are analyzed during heating and cooling using classical models of the kinetics of phase transformations as well as CTA and CCT diagrams for welded steel. The interpolated heat source model is developed in order to reliably reflect the real distribution of Yb:YAG laser power obtained by experimental research on the laser beam profile.

On the basis of developed numerical models the geometry of the weld and heat affected zone are predicted as well as the structural composition of the joint.

Open access

J. Pieprzyca, T. Merder, M. Saternus and K. Michalek

Abstract

The efficiency of vacuum steel degassing using RH methods depends on many factors. One of the most important are hydrodynamic processes occurring in the ladle and vacuum chamber. It is always hard and expensive to determine the flow character and the way of steel mixing in industrial unit; thus in this case, methods of physical modelling are applied. The article presents the results of research carried out on the water physical model of RH apparatus concerning the influence of the flux value of inert gas introduced through the suck legs on hydrodynamic conditions of the process. Results of the research have visualization character and are presented graphically as a RTD curves. The main aim of such research is to optimize the industrial vacuum steel degassing process by means of RH method.