In metallurgy,stainless steel is inox steel with a minimum of 10.5% chromium contents by mass.It have corrosion resistance and is wisely used by many applications.
There are various grade and surfaces finishes of stainless steel to suit the environment the alloy must endure.
Stainless steel differs from carbon steel,special alloy by the amount of chromium,nickel and other chemical compositions.In comparison,stainless steel contain sufficient chromium to undergo passivation,forming an inert file of chromium oxide on the surface.This layer prevents further corrosion by blocking oxygen diffusion to the steel surface and stops corrosion from spreading into the bulk of the metal.
High oxidation resistance at ambient temperature is normally achieved with addition of a minimum of 13% chromium and up to 26% could be used for more harsher environments. The chromium oxide (Cr2O3) is formed then exposed to oxygen.The layer is impervious to water and air,protecting the metal beneath.
About the corrosion acids, stainless steel is generally highly resistant to attack from acids,but this quality depends on the kind and concentration of the acid, the surrounding temperature, and the type of steel.The grade 904 is resistant to sulfuric acid at the normal temperature also can be in even high concentrations;TP316 and TP317 are resistant below 10%,TP304 should not be used in the presence of sulfuric acid at any concentration.All types of stainless steel resist attack from phosphoric acid, TP316 and TP317 are more than TP304.TP304L can be used in nitric acid environment.And of the stainless steel grades are not suitable in hydrochloric acid surroundings.
Superaustenitic stainless steels like alloy AL-6XN and 254SMO,exhibit great resistance to chloride pitting and crevice corrosion because of high molybdenum conent and nitrogen additions.
Send your message to us:
Post time: Dec-05-2017