Molybdenum grade stainless steels

The generic term “Stainless Steel” covers a large group of iron-base alloys that contain chromium. The term “stainless” implies a resistance to staining or rusting in air. Stainless steels contain at least 10.5% chromium, which promotes formation of a thin, chromium-enriched surface oxide. Without this minimum amount of chromium, iron-base alloys or steels corrode in moist air, forming the familiar red rust.

While chromium content determines whether or not a steel is "stainless," molybdenum improves the corrosion resistance of all stainless steels. It has a particularly strong positive effect on pitting and crevice corrosion resistance in chloride-containing solutions.

Stainless steels are grouped in several different types defined by the steel's microstructure. Austenitic stainless steels account for almost 75% of all stainless steels used in the world; ferritic, about 25%; duplex (mixed austenite and ferrite), about 1%; and martensitic about 1%. Composition is the primary determinant of stainless steel microstructure.

To view entertaining and informational video presentations about stainless steel's recyclability, the nature of its protective film, and the role of alloying elements in stainless steel, see the Team Stainless videos:

Stainless Steel Videos