COMPARATIVE ASSESSMENT OF Al-Si ALLOY GASSING DEGREE WITH THE APPLICATION OF THE ‘FIRST BUBBLE’ AND ‘SOLIDIFICATION UNDER DECREASED PRESSURE’ METHODS
DOI:
https://doi.org/10.7494/mafe.2016.42.1.7Keywords:
aluminum alloys, gassing degree, measuring the gas contentAbstract
All aluminum alloys in a liquid state are characterised by easy oxidation and absorption of hydrogen from the surroundings (which are the main reasons for casting defects). The amount of hydrogen adsorbed by a liquid alloy depends mainly on temperature and melting time. The performed investigations were aimed at comparing two known methods of measuring a metal gassing degree; the first bubble method and sample solidification under decreased pressure. Liquid metal melting and holding processes were performed under different conditions that caused variability of its gassing degree, resulting in a variability of purity and quality of the liquid metal. The investigations were carried out with using the hypoeutectic aluminum-silica AK7 alloy.Downloads
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