Stainless Steel is an alloy made of iron, chromium and carbon. Occasionally it has other complementing elements, the most common one is nickel.
Chromium is what gives this material its stainless nature. In oxidising atmospheres, for example air, chromium makes a very dense and thin oxide layer which isolates the material from any corrosive action.
The passive layer should always be maintained undamaged, this guaranties stainless steel high corrosion resistance
Stainless Steels are classified depending on their different containing elements and also on the quantity of each of these elements into their composition.
Generally, four basic families are considered: martensitic, ferritic, austenitic and duplex stainless steels.
Information courtesy of ACERINOX
The condition of the surface of any stainless steel is vital not only for aesthetic purposes, but it has a self-healing surface layer (passive layer) and wears no coatings. The selection of the appropriate finish for a particular application is decisive for a good behavior results with almost no maintenance during its life cycle.
This is a short list of the most common finishes produced by Acerinox, our main associated and Spanish stainless steel manufacturer. Regarding stainless steel finishes normative, we would like to point out that the finish of a surface is determined by its manufacturing process and not, with a few exceptions, by its roughness. For more information, we suggest to see EN 10088-2:2014.