Daniel MOLNAR¹, Laszlo VARGA¹, Csaba MAJOROS²THE SIMULATION OF TILT CASTING PROCESS

Malinowski, K. Liszka, J.S. Suchy
TRAINIG SYSTEM BASED ON ENGINEERS COMPETENCE STAR

Izudin Dugic¹, Salem Seifeddine², Magnus Holmgren¹WAYS TO IMPROVE MECHANICAL PROPERTIES OF RECYCLED ALUMINIUM ALLOYS

Peter Majerič, Darja Jenko, Bernd Friedrich, Rebeka Rudolf
FORMATION OF GOLD NANOPARTICLES WITH ULTRASONIC SPRAY PYROLYSIS

Pezer¹, A. Mahmutovič², I. Anžel³ and P. Mrvar⁴PHYSICAL AND NUMERICAL SIMULATION BASED OPTIMIZATION IN CONTINUOUS CASTING OF CU SMA ALLOYS

Daniel MOLNAR¹, Laszlo VARGA¹, Csaba MAJOROS²THE SIMULATION OF TILT CASTING PROCESS

Abstract

The filling process is the point in manufacture when most of the defects are introduced into the cast part. Tilt casting solutions for gravity pouring could be described as damage limitation exercises. Here a Control Volume model is used to simulate the tilt casting process of a copper based faucet casting. The target of the experiments were to identify the critical process parameters and build a simulation protocol by the help of which several tilt casting processes and geometries can be modelled and examined.

Malinowski, K. Liszka, J.S. Suchy
TRAINIG SYSTEM BASED ON ENGINEERS COMPETENCE STAR

Abstract

Casting is still perceived as one of the most significant methods of manufacturing metal elements. Over the last several years many new solutions and technologies have been developed in this sector which, along with the ever growing demand for casts, have extended the range of their application. More and more frequently, foundries have to face the challenge of adapting their production structure to constantly changing demands of markets, which is feasible by providing the necessary materials, machinery, devices and human resources. In modern times, it is the human resources of the corporation that has grown more and more significant and is commonly regarded as the crucial factor in gaining the competitive advantage. Therefore, in the era of economy based on knowledge, increasing attention has been paid to the staff management, especially in the case of competency. The perception of staff competency (skills, knowledge, experience, abilities) as a key factor for company's success has compelled corporations to search and implement innovative tools to manage them. Competency-based human resources management has been found useful in all staff-related processes - recruitment, selection, employee evaluation, establishing career paths and especially in identifying training needs of employees. With regard to the necessity of constant staff development, a training module based on the elements of competency management system has been devised. It is dedicated to foundry workers, especially casting engineers.

Izudin Dugic¹, Salem Seifeddine², Magnus Holmgren¹WAYS TO IMPROVE MECHANICAL PROPERTIES OF RECYCLED ALUMINIUM ALLOYS

Abstract

The aluminium and aluminium alloys consumption in the world is increasing and continues to find new applications. Aluminium can be produced from the raw material bauxite or by recycling aluminium scrap. When aluminium is being recycled the material strength is depending on the molten metal quality as well as the alloying and trace elements in the aluminium scrap. High demands are put on the material strength of cast products and the market is continuously asking for a material with the right and reliable quality.

This paper aims to investigate ways to improve the mechanical properties of recycled aluminium alloys based upon the Al-Si alloy system. The influence of hydrogen content on internal porosity and the sole effect of the alloying element Si on the mechanical properties have been studied.

The hydrogen content has been measured by Density Index at specific locations in the recycling process (at the smelter) and with different degassing methods. Density Index is a measure for measuring and comparing the samples with respect to the internal porosity. As the air contains moisture, along with the melt temperature, the solubility of hydrogen in the melt is affected. Furthermore, the tensile test results and microscopic investigations reveal clearly that the variations within the alloying element range lead to remarkable differences in the mechanical properties.

Peter Majerič, Darja Jenko, Bernd Friedrich, Rebeka Rudolf
FORMATION OF GOLD NANOPARTICLES WITH ULTRASONIC SPRAY PYROLYSIS

Abstract

Ultrasonic Spray Pyrolysis (USP) is a known method for synthesis of various fine powders. In our previous research work we synthesized different gold nanoparticles (AuNPs) with limited success, as the formation mechanisms were not known for AuNP synthesis with the USP. In order to identify the formation mechanisms and provide greater control over AuNP synthesis, we have modified the USP with a separate aerosol droplet evaporation zone and an introduction of the reduction gas directly into the reaction furnace. A 2.5 MHz ultrasound was used to create aerosol droplets of a solution with HAuCl₄, with gold concentrations from 0.5 to 5 g/l. Nitrogen was used as the carrier gas for droplet transportation into the heating zone (gas flow from 1.5 to 4.5 l/min). Hydrogen gas was used for reduction of the gold chloride into AuNPs (gas flow from 1.0 to 2.0 l/min). Heating temperatures were 50-100°C for the evaporation zone and 300-400°C for the reaction furnace. It was identified that the AuNPs are formed from a combination of the Droplet-to-Particle mechanism, DTP and the Gas-to-Particle mechanism, GTP. The most influential parameters for affecting the ratio between these two formation mechanisms were determined: Gold concentration in the precursor solution and gas flows. Appropriate synthesis parameters have decreased the formation by the DTP mechanism; synthesizing AuNPs mainly by the GTP mechanism and producing more uniform AuNPs, which were not obtained previously.

Pezer¹, A. Mahmutovič², I. Anžel³ and P. Mrvar⁴PHYSICAL AND NUMERICAL SIMULATION BASED OPTIMIZATION IN CONTINUOUS CASTING OF CU SMA ALLOYS

Abstract

The continuous casting process is a widely used attractive technology in modern metal industry. Despite the widespread application due to the inherent complexity from the underlying physics, it is still not well understood. The objective of this paper is to model the thermo-mechanical behavior in continuous casting of Cu based SMA alloys. A coupled thermo-mechanical numerical simulation of solidifying rod is implemented in ProCAST software suite capable of modeling process under full non-equilibrium process conditions. The model is applied to calculate full time dependent temperature and stress distribution during continuous casting. Special focus has been the identification of the solidification front sensitivity on the various process parameters: casting speed, thermal contact conductivity and water cooling system thermal efficiency. The stability of the solidification front profile is examined and typical process parameters are proposed. Results from the simulations compare favorably with experimental experience that one of the key parameters is casting speed full time dependent profile.