1. what is stainless steel?


In metallurgy, stainless steel, also known as inox steel orinox from French "inoxydable", is a steel alloy with a minimum of 10.5% chromium content by mass.


2. what are the properties of stainless steel?


Stainless steel does not readily corrode, rust or stain with water as ordinary steel does, but despite the name it is not fully stain-proof, most notably under low oxygen, high salinity, or poor circulation environments. There are different grades and surface finishes of stainless steel to suit the environment the alloy must endure. Stainless steel is used where both the properties of steel and resistance to corrosion are required.


Stainless steel differs from carbon steel by the amount of chromium present. Unprotected carbon steel rusts readily when exposed to air and moisture. This iron oxide film (the rust) is active and accelerates corrosion by forming more iron oxide, and due to the greater volume of the iron oxide this tends to flake and fall away. Stainless steels contain sufficient chromium to form a passive film of chromium oxide, which prevents further surface corrosion by blocking oxygen diffusion to the steel surface and blocks corrosion from spreading into the metal's internal structure, and due to the similar size of the steel and oxide ions they bond very strongly and remain attached to the surface.


Passivation only occurs if the proportion of chromium is high enough and oxygen is present.


3. how many stainless steel finishes are there?


Standard mill finishes can be applied to flat rolled stainless steel directly by the rollers and by mechanical abrasives. Steel is first rolled to size and thickness and then annealed to change the properties of the final material. Any oxidation that forms on the surface (mill scale) is removed by pickling, and a passivation layer is created on the surface. A final finish can then be applied to achieve the desired aesthetic appearance.


· No. 0: Hot rolled, annealed, thicker plates


· No. 1: Hot rolled, annealed and passivated


· No. 2D: Cold rolled, annealed, pickled and passivated


· No. 2B: Same as above with additional pass-through highly polished rollers


· No. 2BA: Bright annealed (BA or 2R) same as above then bright annealed under oxygen-free atmospheric condition


· No. 3: Coarse abrasive finish applied mechanically


· No. 4: Brushed finish


· No. 5: Satin finish


· No. 6: Matte finish (brushed but smoother than #4)


· No. 7: Reflective finish


· No. 8: Mirror finish


· No. 9: Bead blast finish


· No. 10: Heat colored finish-wide range of electropolished and heat colored surfaces