The Use of Nitrogen to Degas Molten Aluminium-Comparison of Metallurgical Results with Argon and Nitrogen Used in an ACDtm

摘要

The use of argon to degas molten aluminium is a widespread practice in aluminium casthouses, and the removal of the hydrogen contained in the metal by using this noble gas is a proven method with no downside effect on the metallurgical quality of the resulting metal. On the other hand, an increasing number of producers are looking for cost reduction opportunities, and nitrogen often comes as an alternative to replace argon to degas molten aluminium. However, some are questioning the degassing efficiency of this gas or the risk to deteriorate metal cleanliness. STAS Inc. has carried out a series of comparative tests, using argon and nitrogen in an ACD. Metallurgical measures for degassing and metal cleanliness have been taken to compare both gases. This paper presents the results obtained during this test campaign carried out in North America.