Erosion Of Refractory And Its Effect On Steel Quality In Two-phase Flow

In the steelmaking process,the erosion of molten steel was one of important factor that refractory was damaged.In this paper,the erosion behavior of Al-Mg refractory and their relationship with inclusions in two-phase flow were studied using erosion test of argon stirring in the molten steel and combining water model and numerical simulation,the mathematical model of erosion was established according to the mechanism analysis of erosion.The results provided the advice for improving refractory life and steel quality.The main conclusions were listed in the follow:(1)The erosion rate of Al-Mg refractory can be expressed as function of the erosion coefficient and the high-temperature critical shear strength of refractory.The formula of refractory erosion was obtained using dimensional analysis method based on the results from the erosion test of high-temperature molten steel,water model and numerical simulation.(2)The erosion of refractory started at the matrix by erosion test with corundum refractory,magnesia refractory and alumina-magnesia refractory.When the shear stress was higher than the critical shear strength,the matrix was peeled off,holes and slits were formed,and the molten steel penetrated into the matrix.When the matrix around the aggregate were eroded away by the molten steel,the aggregate exposed in the molten steel and then peeled off.The erosion rate increased at first and then decreased with time.Alumina-magnesia refractory had better erosion resistance than corundum refractory and magnesia refractory.(3)The number of inclusions in steel gradually increased with erosion time,and some small inclusions would gather and grow.Different phase of refractory were present in the molten steel after being eroded by molten steel which affected the steel quality.(4)The turbulent flow of gas-liquid was formed near the surface of refractory due to the movement of bubbles.It was similar to the turbulent flow near the surface of refractory in the argon blowing tundish,The method could be used to simulate the erosion of refractory by the actual flow of molten steel.The molten steel velocity andturbulent gradually increased with the increasing of gas flow rate,the molten steel velocity and turbulent kinetic energy were high,and resulted in the higher shear stress.The equation for the erosion of Al-Mg refractory by molten steel was obtained based on the results of numerical simulation and experiment of erosion.