It is a chemical element that increases the hardening depth of steel and its toughness. Austenitic stainless steels contain molybdenum to improve their resistance to corrosion.
As an alloying element in steels, it increases the hardenability and decreases the brittleness in the tempering .
Molybdenum hardens the ferrite in the steel matrix and forms carbides, which produces an increase in strength, yield strength and hardness, maintaining these characteristics at elevated temperatures.
In stainless steels it is used for applications where steel will have service conditions with temperatures up to 300ºC. It can be used to improve resistance to corrosion.