Discussion of bi-film index and LiMCA data in industrial aluminum remelting trials

Abstract

The trend in the aluminum high end market is to set unrealistic quality requirements e.g. inclusion free metal. The importance of quality and the ability to measure is growing. LiMCA is a unique, well-established tool for monitoring inclusions in molten aluminum. However, the cost of LiMCA and/or availability sometimes becomes a problem. The “old” vacuum test has long been a simple tool for qualitative analysis of the quality. This vacuum method has been developed further into a quantitative method for estimating metal quality in terms of a bi-film index. In this paper, industrial remelting trials are presented where both bi-film index and LiMCA measurements were performed. The two measurement techniques are compared. The conclusion is that the bi-film index and LiMCA demonstrate a similar behavior with time. Thus, the bi-film index may become an additional tool also for quantitative analysis of aluminum quality.