However, niobium is strong carbide former and modifies the solidification sequence of the steel. In the first stage of solidification, niobium-rich MC carbides are formed [5]. In addition, increasing the niobium content in steel up to a mass fraction of approximately 1.8 % causes an increase in hardness, the wear resistance and the toughness compared to the material without niobium. The affinity of niobium for carbon is greater than that of vanadium.