Measurements of surface tension of the melts of iron and alloys on its base were conducted by F. Saurwald and his associates in 1929. The surface activity of rare-earth elements in iron and steels was studied in connection with their use for steel alloying. In addition to the metal composition, the value of surface tension of the metal melt is essentially influenced by the composition of the gaseous medium contacting the metal. Methods of drop weight and pendant drop were used by us to determine the values of surface tension of some titanium-based alloys, which are often applied in the fabrication of welded structures, at their melting temperature, in argon and hydrogen atmosphere. In submerged-arc or covered-electrode welding and surfacing, as well as in electroslag processes, the molten metal is in contact with the slag. Composite materials, where boron fibers are used, and aluminum is the matrix, are applied in industry.