The Mechanism of Slag Attack on Pitch - Bearing Dolomite BOF Refractories
신건 , 김성만 Geon Shin ad Sung Man Kim
Abstract
The samples of used doloma-containing basic refractories of POSCO`s 300 ton capacity BOF have been taken and made into thin-sections for optical and electronic microscopic investigation to characterize the failure mechanism of the lining in the steelmaking conditions. A striking contrast has been found in the thickness of decarburized zone between those two refractories of POSCO and a Japanese steelmaker in the almost similar steelmaking and refractories practices. The decarburized zone thickness of POSCO`s lining is extremely thin. The opposite is true of that of the Japanese steelmaker. The difference in the thickness of decarburized zone in relation to the protective nature of the carbon-containing MgO-based brick has been studied mainly based on a mathematical model pertaining to the formation of the dense MgO layer close to the hot face of the brick. This study shows that maintenance of a thicker decarburized zone is one of the critical parameters involved in the extension of lining life of the BOF refractories.