Interesting facts about Niobium/Columbium and Tantalum in steel

Melting point 2468 °C
Melting point 2996 °C

These elements occur almost exclusively together and are very difficult to separate from one another, so that they are usually used together. Very pronounced carbide formers, thus alloyed particularly as stabilizers of chemical resistant steels. Both elements are ferrite formers and thus reduce the γ-phase. On account of the increase in high temperature strength and creep rupture strength due to Nb, it is frequently alloyed to high-temperature austenitic boiler steels. Ta has a neutron high absorption cross-section; only low-Ta Nb is considered for use for reactor steels.