Model Based Optimisation of Aluminium Wire Injection in Steel Melts

摘要

(1) A mathematical model was developed to study the behaviour of aluminium wire injected into the molten steel bath. The model can be utilised to assess the influence of various factors on the utilisation efficiency of aluminium injection and thus arrive at the optimum operating condition to achieve maximum utilisation. (2) The model revealed that melting of the wire in the liquid steel bath could take place through two different routes viz. with formation of a secondary shell or without formation of the secondary shell, depending on the operating parameters. Formation of the secondary steel shell was found to be beneficial since it delayed the wire melting process and thereby allows the wire to penetrate deeper into the melt. (3) The point of release of the molten aluminium in the bath depends on factors like wire dimension, wire injection speed, bath superheat etc. No dependence of the wire melting behaviour on the grade of steel being processed was found. (4) The solution for the problem of unpredictable utili- sation of Al in case of wire injection process can be achieved by a reduction in the injection speed with simultaneous increase of the wire diameter from 12.5 mm to 16 or 18 mm.