Analysis of magnesium carbon brick problems in the short process of induction furnace refining

During the induction furnace steelmaking process, due to raw material limitations, some iron oxide scale needs to be added to reduce the carbon content of the molten steel. Then, a large amount of iron oxide scale is added to further dilute the carbon content. However, since iron oxide scale contains a large amount of FeO, FeO readily reacts with graphite in magnesia-carbon bricks at high temperatures, producing bright white iron beads and forming a decarburization layer. Furthermore, the periclase in the magnesia-carbon bricks also reacts with FeO in the furnace to form low-melting-point products.

During the repeated heating and cooling of the ladle, the inconsistent thermal expansion rates between the formed magnesium-iron composite low-melting-point product and magnesioferrite cause the magnesium oxide on the refractory surface to fracture, leading to the dissolution of the brick body. FeO accelerates the oxidation of carbon on the surface of the magnesia-carbon brick, and FeO reacts with MgO, making the working surface of the magnesia-carbon brick loose. These two factors together accelerate the erosion of the magnesia-carbon brick. The loose structure of the decarburization layer, under the action of thermal expansion and slag scouring, produces larger cracks and pores, allowing slag to easily penetrate and form a low-melting-point phase with MgO. Simultaneously, under the intense mechanical agitation of the molten pool and the violent scouring of the steel slag, the surface structure of the magnesia-carbon brick changes, gradually deteriorating from the outside in, resulting in severe damage to the magnesia-carbon brick. When the temperature exceeds a certain value, the brick structure is destroyed, leading to rapid erosion.

In the process of induction furnace steelmaking, due to the limitation of raw materials, some iron oxide (iron scrap or iron scale) needs to be added to reduce the carbon content of the molten steel, and then more iron oxide (iron scrap or iron scale) is added to dilute the carbon content in the molten steel; however, because it contains a large amount of FeO, FeO at high temperatures

easily undergoes an oxidation reaction with graphite in magnesia-carbon bricks, producing bright white iron beads and forming a decarburization layer.

In the process of repeated heating and cooling of the ladle, the thermal expansion rate between the formed Mg-Fe composite low-melting-point product and Mg-Fe

is inconsistent, causing the magnesium oxide on the refractory surface to fracture and leading to the dissolution of the brick body. FeO accelerates the surface of the magnesia-carbon brick

oxidation of carbon, and the subsequent reaction of FeO with MgO makes the working face of the magnesia-carbon brick loose.

This accelerates the erosion of the magnesia-carbon brick. Secondly, the loose structure formed by the decarburization layer is more susceptible to thermal expansion and slag scouring,

resulting in larger cracks and pores, allowing slag to easily penetrate and form a low-melting-point phase with MgO. Meanwhile, the vigorous mechanical agitation and steel slag scouring in the molten pool

alter the surface structure of the Mg-C brick, causing gradual deterioration from the outside in, resulting in severe damage to the Mg-C bricks. When the temperature exceeds a certain value, the brick structure is destroyed, leading to rapid erosion.