Analysis of effect of calcium content on machinability of alloys type AlSi7Mg0.3
2019
Strihavkova, E., Jan Evangelista Purkyne Univ. in Usti nad Labem (Czech Republic)
The choice of aluminium alloy for casting is subject to a number of the basic criteria such as strength, shape, precision, surface quality, weight, corrosion resistance, etc. The structure, and in particular the mechanical, technological and chemical properties of aluminium alloys type Al–Si (silumines) may be affected primarily by modification and addition of the inoculants. The paper deals with the research in the field of new AlSi7Mg0.3 alloys with different calcium content and especially the machinability of the alloy. For experimental purposes an aluminium alloy from the group of hypoeutectic silumin AlSi7Mg0.3 was used. Alloying took place using calcium in the form of AlCa10 alloy. A total of 4 melts were cast. The first without addition of AlCa10 pre-alloy and the other three with graduated calcium, up to 0.1 %, 0.5 % and 1 % Ca. The specimens thus prepared were subjected to a spectrographic analysis of the chemical composition to confirm the added calcium content. Subsequently, an analysis of the technological properties and especially of the machinability was carried out. In the last part, there were the chips evaluated produced during the machining of the experimentally produced alloys. To measure the chip size, it is possible to determine the sludge effect on the shape and size of the chip, as only certain types of chips are required during processing, namely, which are most suitable for the continuity of the machining process. Another reason for chip analysis was the change of the chip shape in the case of wear of the cutting tool during the cutting process. This topic is currently very topical in view of the high requirements of material parameters, especially in the automotive industry.
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