Columbium

Element, chemical symbol Cb, also known as Niobium (Nb). This metal may be added to chrome-nickel stainless steel to improve its welding qualities by preventing carbide precipitation. A refractory metal used as an alloying agent in steel making, it is essential for high-strength, low-alloy grades and helps in terms of grain refinement and hardenability. It has some “worked metal” uses, mostly alloyed with zirconium or titanium for aerospace applications.