Vacuum Testing of Aluminum

摘要

The use of vacuum solidification tests to assess aluminum melt quality goes back at least to the early 1920s and is generally acknowledged to have been first commercialized with an apparatus to perform the Straube-Pfeiffer test. In North America, Reduced Pressure Test (RPT) is the name commonly used for this procedure. Over the years, many attempts have been made to relate the test results on small solidified samples to the actual hydrogen level in the melts with the correlations somewhat marginal. The correlation problem is recognized to be caused by many factors in the testing and equipment, and also the quantity, size, shape, and type of inclusions present in the melt. Inclusions also exercise control over the number of pores that will develop in solidification of any product made with the melt contamination, be it castings or material subsequently used in extrusions, forgings, or other aluminum products. The RPT will give an early indication of the presence of inclusions.