Abstract: The wettability measurement between MgO, MgAl₂O₄ and MgO-CaO refractories and the molten heavy rail steel was carried out using the sessile drop method at 1 550 ℃. The penetration of the molten steel to different refractories and the effect of different refractories on the steel cleanliness were analyzed using a scanning electron microscope after the wetting process. Results showed that the initial contact angels between MgO, MgAl₂O₄and MgO-CaO refractories and the molten heavy rail steel were 116.8°, 133.5° and 147.1°, while the equilibrium contact angles were 97.6°, 91.0°, and 109.4° at 1 550 ℃, respectively. The MgAl₂O₄ refractory was eroded by the heavy rail steel, leading to the formation of magnesium aluminum spinel inclusions on the surface of steel ball. Besides, the MgAl₂O₄ refractory was easily penetrated by the molten steel with the average penetration depth of 163.4 μm.A dense reaction layer was formed at the interface between MgO-CaO refractory and the molten steel. The reaction layer hindered the penetration of the molten steel into the MgO-CaO refractory, but the reactants were involved into the molten steel and spread out on the surface. The interaction between the molten steel and the MgO refractory was the weakest. MgO refractory hardly affected the steel cleanliness, and was weakly corroded by the molten heavy rail steel.

Key words: refractory, heavy rail steel, contact angle, wettability, permeation