RELATIONSHIP BETWEEN THE REDUCED PRESSURE TEST AND HYDROGEN CONTENT OF THE MELT

摘要

The Reduced Pressure Test (RPT) is an inexpensive, foundry floor test which allows the metalcaster to qualitatively assess the cleanliness of a batch of molten aluminum, allowing corrective action to be pursued. A previous study examining various sampling techniques and sample density evaluation methods resulted in the development of a statistically optimized test method for the RPT. This study examines the correlation of RPT densities to recirculating gas hydrogen measurements, specifically ALSCAN measurements, in 356 alloy which has not been grain refined nor modified. A range of melt temperatures and oxide levels was used in the development of each curve. The correlation curve developed in this study extends the usefulness of the optimized RPT test method to allow indirect measurement of the hydrogen content of 356 melts. The correlation curve presented here together with the prescribed RPT methodology can be used by the industrial sector to obtain on-line information about the metal quality.