Stainless steel does not rust and is due to the corrosion resistance of chromium - rich oxide film on its surface ( film - ) formation. This does not rust and corrosion resistance are relative. Tests show that steel in weak medium such as air, water and nitric acid oxidizing medium and its corrosion resistance increase with the increase in moisture content of chromium in steel, when the chromium content reaches a certain percentage, mutation of the corrosion resistance of steel, rusted from easy to difficult to get rusty and never corrosion resistance to corrosion. Many classification method of stainless steel. By at room temperature Xia of organization structure classification , has horse 's body , and Olympics 's body , and ferritic and double phase stainless steel ; by main chemical components classification , basically can is divided into chromium stainless steel and chromium nickel stainless steel two large system ; by uses min is has resistance nitric acid stainless steel , and resistance sulfate stainless steel , and resistance seawater stainless steel and so on , by resistance corrosion type min can is divided into resistance points corrosion stainless steel , and resistance stress corrosion stainless steel , and resistance Crystal between corrosion stainless steel , ; by function features classification and can is divided into no magnetic stainless steel , and easy cutting stainless steel , and low temperature stainless steel , and high strength stainless steel and so on . Due to the stainless steel material with excellent corrosion resistance and formability, compatibility, and in a wide temperature range characteristics of strength and toughness of the series, so in heavy industry, light industry, supplies industry and building decoration industry is achieved in a wide range of applications.
316 cold rolled stainless steel welded tube