Stainless steel is a steel alloy that contains at least 10% chromium, making it corrosion resistant. The addition of chromium to stainless steel creates a thin film of metal oxide over the metal's surface that protects against corrosive materials.

A popular grade of stainless steel is stainless steel 316 is generally composed of 16 to 18% chromium, 10 to 14% nickel, 2 to 3% molybdenum, and a small percentage of carbon. Adding molybdenum to stainless steel 316 increases its corrosion resistance compared to other grades of stainless steel. The addition of other alloys further enhances its properties.

The properties and characteristics of stainless steel 316 make it the second-most widely used stainless steel grade after stainless steel 304. It is used in corrosive environments such as chemical plants, refineries, and marine equipment.

Stainless steel 316L has a lower carbon content and is used in applications that subject the metal to risks of sensitization. The higher carbon variant is stainless steel 316H, which offers greater thermal stability and creep resistance. Another widely used grade of stainless steel 316 is the stabilized 316Ti. Stainless steel 316Ti offers better resistance to intergranular corrosion.

Stainless steel utilizes the principle of passivation, wherein metals become "passive" or unreactive to oxidation from corrosive compounds found in the atmosphere and process fluids. Passivation is done by exposing the stainless steel to air, where it builds chromium oxides on its surface.

To enhance the formation of the passive film, the alloy is introduced to a chemical treatment where it is thoroughly cleaned by submerging it in acidic passivation baths of nitric acid. Contaminants, such as exogenous iron or free iron compounds, are removed to prevent them from interfering in creating the passive layer.