Method for measuring hydrogen in aluminum by vacuum fusion extraction

Abstract

The characteristics of crucibles made of graphite, mullite, alumina, and stainless steel (SUS 27) were examined for the purpose of retaining a molten aluminum sample in the extraction tube of gas measuring apparatus. The gas volume extracted by these crucibles or blank gas volume was measured, and hydrogen contents of aluminum samples were also measured from vacuum fusion extraction method by using these crucibles.The results showed that a crucible made of SUS 27 was more excellent in characteristics than those of other ones. Then, the following tests were conducted by using the SUS 27 crucible.(1) Reliability of measured values of hydrogen in aluminum obtained by vacuum fusion extraction method.(2) Distribution of hydrogen in the aluminum castings poured into the Ransley's chill mold.(3) Correspondence of the measured values with those by solid extraction method.The results obtained were as follows:(1) Standard deviation of the measured values of hydrogen in extruded aluminum rod was 0.003cc/100g.(2) Distribution of hydrogen in the castings poured into the Ransley's chill mold was not uniform.(3) Measured values by vacuum fusion extraction method corresponded well with those by vacuum solid extraction method.