Molybdenum (often called “molybdenum”) has many important uses in alloy steels, stainless steels, alloyed cast irons and superalloys. Molybdenum is an effective hardening agent and is a component of many heat-treatable alloy steels.

It retards softening at high temperatures and therefore can be used in boiler and pressure vessel steels, as well as in many grades of high-speed steel and other tool steels. Molybdenum improves the corrosion resistance of stainless steel.

In HSLA steel it produces an acicular ferrite structure. Molybdenum is the basis for several rolled dual-phase steels used in automotive applications. While molybdenum is often used interchangeably with chromium and vanadium, in many cases the properties it imparts are unique. As a result, its use has increased significantly over the past few decades, with demand often exceeding supply.

Molybdenum is supplied as ferro molybdenum. Ferro molybdenum contains at least 60% Mo. Silicon and copper content can be up to 1%. A relatively expensive and rarely used alloy additive, ferromolybdenum is packaged in cans or bags to prevent handling losses.