“ALCOA Samara Metallurgical Plant” JSC, Samara, Russia:

A. E. Afanasev, Chief Metallurgist, e-mail: alexandr.afanasiev@alcoa.com
E. G. Kandalova, Manager of Technological Development Office

The paper gives the review of technology of slabs' production from 3104 and 5182 aluminium alloys for manufacturing of can stock at Samara Metallurgical Plant. The basic attention is paid to high requirements to metal purity, according to nonmetallic inclusions, which is connected with special conditions of deep ironing, high forging speeds during can manufacturing and can mass decreasing tendency (decreasing of stock thickness). There are shown the basic types of non-metallic inclusions and their formation during ingot production. Practice shows that the main problems are inclusions, which are formed during certain operations, such as: melt overheating; long holding of melt in melter or holde; nonobservance of melt drossing; melt turbulence; improper maintenance of melter, holder, filter box and troughs refractory. There is described the modern system of melt purification, including the following operations:
— in-line fluxing with Ar and Cl mixture;
— mixture filtration through deep bed filter and foam ceramic filter;
— melt distribution and flow control in the mold.
Evaluation of melt purity with PoDFA showed the reduction of amount of inclusions in metal by almost two orders, using this filtration system. At the same time it is important not only to use all elements of filtration system, but also to do the strict following of procedures of regular cleaning of melter and holder, melt drossing in melter, holder, degasser and deep bed filter. It is also important to do the careful preparation and cleaning of troughs, filter box and spouts before casting. Nonobservance of any of these procedures increases the risk of claims on non-metallic inclusions significantly.

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