On this page
Why can small additions matter?
An alloy is not defined only by its most abundant element. Small amounts of niobium or vanadium can make important contributions to strength, internal structure and temperature response. Their names may therefore refer either to a separate material or to an addition within a steel or titanium alloy.
Niobium has the symbol Nb and vanadium the symbol V. Older or American material documents may use columbium and the symbol Cb for niobium. These are not two different elements. The older designation is particularly relevant when reading historical descriptions of nickel alloys.
Niobium in stainless and nickel alloys
In 347 stainless steel, niobium combines with carbon and contributes to corrosion behaviour after thermal exposure. This is known as stabilisation. The compounds in which carbon is present matter to stainless-steel performance, so the role of niobium involves more than its percentage alone.
In Alloy 718, an important role of niobium is its participation in the structures responsible for high strength. The same element can therefore be associated with stabilisation in one stainless steel and strengthening in a superalloy. The examples show why an element name alone does not describe the use of the complete alloy.
Vanadium in steel and titanium
Vanadium helps develop strength in various steels through small, hard compounds. Automotive components, springs and high-strength steels are examples. Greater strength can sometimes allow a lighter component to carry the required load, though the result depends on the full set of material properties.
The V in Ti-6Al-4V also means vanadium. In this case it is a principal addition shaping the structure and properties of the titanium alloy. Its role in titanium differs from that of a small vanadium addition in steel because both the base metal and the alloy system have changed.
Pure metals and alloys are different products
Pure niobium, niobium-based specialty alloys and niobium-bearing stainless steels are separate materials. Vanadium metal, ferrovanadium and a vanadium-bearing steel likewise refer to different products. Ferroalloys are materials used as alloying additions in metal production rather than names for finished steel grades.
The use of 347 stainless in hot equipment, Alloy 718 in high-strength connections and Grade 5 titanium in lightweight structures illustrates this variety. An alloy derives its properties from how niobium or vanadium works with the base metal and the other additions.