Experimental examination of slag/refractory interface

Abstract

diVerent thermal expansion coeYcients) which, during the subsequent heating and cooling cycles of the ladle, results Ladle glazes are a thin coating of slag formed when in stresses and eventually to 'spalling' of the refractory. the top slag comes in contact with the refractory Thus, the aims of this research programme were to during draining of the ladle. It is believed that ladle obtain direct evidence that ladle glazes are a major source glazes are a major source of inclusions in the next of inclusions; to study the factors in uencing the adhered cast of steel held in that ladle. Pilot plant trials, slag layer, in particular, the thickness of this layer; and to simulation tests, and thermophysical property study the factors controlling the formation and the depth measurements have been carried out on the glazes of slag penetration. to: (i) obtain more information about ladle glazes and the factors affecting their formation and GLAZE FORMATION subsequent removal from the refractory; (ii) provide direct evidence that glazes are a major source of Pilot plant trials were carried out on a 4 t ladle lined with inclusions; (iii) study the factors affecting the (MgO +3% C) bricks and with a rammable MgO base. formation, adhesion, and thickness of the glaze; (iv)The ladle was allowed to cool after each cast and was then study the formation of the slag penetrated layer and reheated for each subsequent cast. A short sequence of the factors affecting penetration. Doping trials have representative steel grades was then cast in the ladle (the last shown that ladle glazes are a major source of being an aluminium killed steel). The ladle was carefully inclusions. The calculated thickness of the adhered dismantled and examined. slag layer was appreciably lower than measured experimental values. Calculated horizontal slag Characteristics of glaze infiltration depths were in reasonable agreementThe following observations were made from examinations with values measured on plant, but measured of the specimens of refractory plus glaze: vertical infiltration depths were much lower than (i) the glaze thickness was 10-15 mm in the bottom calculated values. It has been shown that slag half of the ladle, but tended to be both thicker and penetration can be significantly reduced by the more variable in the upper part of the ladle (Fig. 1a) application of an electrical potential.I&S/1682 (ii) microscopic examination of specimens taken from diVerent heights in the ladle revealed a clear interface Dr Riaz and Mr Bain are at the Corus Group Teesside Technology between the refractory and the slag impregnated Centre, Grangetown, Middlesbrough, UK and Professor Mills is in region in the decarburised region of the refractory the Department of Materials, Imperial College, London SW7 2BP, UK

Chemical Reaction of Glazed Refractory with Al-deoxidized Molten Steel

“…The ladle lining (refractory) in their study was magnesite refractory (carbon-bearing MgO lining). Riaz et al 7) and Hassall et al 8) also performed similar studies on the plant ladle treatment with magnesite refractory. The primary concerns of previous studies were to identify the inclusions and to correlate the melt cleanliness (the number of inclusion) and ladle age.…”

“…The feasibility of the physical detachment can be supported by the microstructure of the glaze layer showing the existence of spinel particles on the interface of glaze and molten steel. Several previous studies [7][8][9][10][11] for the ladle glaze of a magnesite lining also suggested that the particles like MgO originally formed in the glaze layer can be retained in the liquid steel as inclusions. For example, Beskow and Du Sichen 10) reported that the complex inclusion of liquid CaO-Al 2 O 3 (-MgO-SiO 2 ) bearing MgO particles, one of the typical inclusions in a practical ladle treatment, was most probably originated from the ladle glaze itself.…”

“…In particular, refractory materials have been indicated as one of the major sources of non-metallic inclusions in the molten steel during ladle metallurgy. [1][2][3][4][5][6][7][8][9][10][11] Upon the discharge of molten steel into a tundish, the top slag moves down together with the molten steel, causing the molten slag to adhere onto the ladle wall, and freeze when cooled down. This slag film adhered to the ladle refractory is called "ladle glaze".…”

State of the art in the control of inclusions during steel ingot casting

“…[191] slag melt [89,152,153] ) found that ''glazed refractories'' and ''reaction layers at the surface of bricks'' formed with molten steel at 1550°C to 1600°C. [151,153,200] The compositions of manganese aluminosilicate inclusions (MnO-Al 2 O 3 -SiO 2 system) found in forgings, ladle glaze analysis, and reaction layers formed between refractory and liquid steel are compared in Figure 31. [88] In this figure, the liquid steel is killed mainly by silicon and manganese alloys and a small amount of aluminum.…”

“…Lining refractory [89,[148][149][150][151][152][153] Analysis of the lining refractory composition before and after operations can be used to estimate inclusion absorption to the lining and the lining erosion. Also, the origin of a complex oxide inclusion can be traced to lining refractory erosion by matching the mineral and element fractions in the slag with the inclusion composition.…”