Results of a study of the wettability of the tundish periclase lining by molten steel using a sessile drop method are presented. The wetting angle q tends to decrease with increase in temperature and contact time on adding glass fiber and Fe 2 O 3 powder in excess of 2% to the magnesite powder; a similar effect is observed in steels high in manganese. An increase in angle q is observed on adding carbon fiber or glass fiber (not in excess of 1%) to the magnesite powder; the angle q tends to increase with increase in MgO powder grain size and with carbon contained in steel in excess of 0.04%.In recent years, there has been an increased demand for steels with a low impurity content. Technologically, the tundish ladle is the last refractory-lined vessel in which the molten steel is processed metallurgically before pouring into molds. MgO-based refractory materials are preferred for making the hot layer of the refractory lining of the tundish ladle. To increase the strength of the lining (normally applied using a gunning technique), additives are introduced into the gunning mix -paper fiber (coarse-or fine-fibrous), mineral wool, glass fiber, expandable clay, and polystyrene beads [1 -3].The interaction between tundish lining and molten steel and slag is an important concern for manufacturing high-purity steels. This interaction involves two related phenomena: wetting and reaction between the three components, which determines the service life of the refractory and the properties of molded preforms, slabs, and blooms [4,5]. To determine the wettability of a solid substrate by molten metal, Young's equation is conventionally used [6]:where q is the wetting angle, deg; g SV is the surface tension of the solid; g SL is the energy of surface interaction between the liquid and the solid; g LV is the surface tension of the liquid. As is known, the liquid wets the solid if q < 90°; in unwettable systems, it is q > 90°.Data have been reported on the wettability of various refractory surfaces [7 -21] by molten iron and steel [7 -9] and on their interaction with gas media [7 -9, 11, 21] and molten slag [7 -9].In [13 -16], the wettability of aluminosilicate refractories by steel or iron was studied; in [17], the effect of Steel 35 on corundum composites was studied, and in [20], the wetting angle q at zirconium surfaces and molten iron was measured. MgO is the most widely used material for manufacturing the tundish lining; still, data on the wettability of periclase lining by molten steel and the effect of additives on wettability are sadly lacking [7,22]. Therefore our goal in this work was to study the wettability of MgO by molten steel. EXPERIMENTALThe low-carbon steels were made available from the Eregli Iron and Steel Works (Turkey); their composition is given in Table 1. The tests were carried out by a sessile drop method; the test specimens were cubes of steel weighing about 0.3 g; the substrate was a magnesite powder of composition, wt.%: MgO, 95.08; SiO 2 , 2.49; CaO, 1.73; Fe 2 O 3 , 0.54; Al 2 O 3 , 0.16. The powde...