METHOD OF DETERMINATION OF STAGES OF CHARGE MELTING IN ELECTRIC ARC STEEL MELTING FURNACE Russian patent published in 2000 - IPC

FIELD: metallurgy; making steel in steel melting furnaces. SUBSTANCE: proposed method consists in measuring the power requirements and extraction of higher harmonics from arc current; seventh and ninth harmonics are extracted from non-sinusoidal voltage of arc and their magnitudes are measured; charge melting and metal heating stages are fixed according to change of magnitudes of seventh and ninth harmonics of voltage of arc depending on amount of consumed electric power. In case of reduction of magnitudes of seventh and ninth harmonics of arc voltage (till their complete disappearance) in melting the charge, adding stage is determined. In case seventh or ninth harmonics of arc voltage appear or abruptly increase in heating the metal, reduction of degree of shielding the arcs by slag is determined. EFFECT: enhanced accuracy of fixing the charge melting and metal heating stages. 3 cl, 4 dwg