Niobium is used as an alloying additive for stainless steels, special stainless steels (e.g. tubes for hydrochloric acid production) and non-ferrous alloys, as niobium-alloyed materials are characterised by increased mechanical strength. Even in concentrations of 0.01 to 0.1 mass percent, niobium in combination with thermomechanical rolling can significantly increase the strength and toughness of steel. The first tests on the use of niobium as an alloying element (replacement of tungsten) were carried out in the USA in 1925. Steels refined in this way are frequently used in pipeline construction. As a strong carbide former, niobium is also alloyed in welding consumables to bind carbon.