The quality of the finished products is influenced by many factors. One of them is casting machine, but even in case of using appropriate casting parameters and it’s correct operation, in certain cases the appropriate quality of castings (shrinkage porosity, impurities in the castings …) is not achieved. Another very important factor influencing the quality of castings is preparation of the melt, where the melting process, degassing process, and transportation of melt to the casting machine must be appropriate. On quality of the products has a great influence also quality of the incoming material, which analysis was the topic of this master's thesis. Influence of the incoming material (ingots) quality on the quality of the castings was analyzed, whereby defects occurred in the castings and consequently the scrap, although all the above-mentioned factors (operation of the casting machine and preparation of the melt for casting) were always the same.
In the first part of the thesis, the production process (from melting process to final machining process) from AlSi12Cu1(Fe) alloy. In the case of an increased scrap percentage after final machining process, the ingot from the batch that was melted in this period was taken. On seized ingots, the condition of the surface, the presence of impurities on the surface as well as inside of the sample and the percentage of porosity were analyzed. In the second part of the thesis, the influence of material quality on solidification and microstructure, which have a direct impact on the mechanical properties of the products, were analyzed. The amount of slag formed during the re-melting was also monitored. The main objective of the thesis was to determine how the quality of certain alloy batches influence the occurrence of defects in the final products. It was established, that the quality of the incoming material significantly affects the overall manufacturing efficiency (melting and casting), the occurrence of the defects in the products and consequently on the scrap rate. The quality of the incoming material must be of good and adequate, as the poor quality of the material cannot be completely corrected during the melting process.
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