Desenvolvimento do processo de sopro com lança de 3 furos no convertedor AOD-L da ArcelorMittal Inox Brasil

Abstract

The AOD converter is the main equipment used on the stainless steels production. The production of stainless steel in AOD-L occurs through injection of a mixture of oxygen and inert gas by tuyères and blowing oxygen by one top lance on the metal bath, to promote the selective carbon oxidation. The process time depends of the nozzle design and the oxygen flow rate. The interaction between the oxygen blown by top lance and the gas injected by the tuyères has an influence on the refine reactions, on the quantity of metal/slag projections and directly affects the metallurgical process results on the AOD-L converter. This work shows the main reasons of the experiment using 3 hole lance in the AOD converter of ArcelorMittal Inox Brazil, replacing the 4-hole lance to blowing oxygen. This work was based in one biography research and the experience of others stainless steel producers to define the configuration of the 3 hole lance used in the experiments. The three holes lances had its opening angle and diameter of the nozzle modified. The experimentswere performed on austenitic stainless steel P304A on the route (EAF-EAF), which uses pre metal from electric arc furnaces and on the route (EAF- PTG) that uses pre metal from the electric arc furnaces and hot metal treated. Using the 3 holes lances the chromium oxidation decreased, the AOD process time reduce, the oxygen and argon specificconsumption reduce, improve AOD desulfurization efficiency with better quality of the cold- rolled strip