Definition of stainless steel: a high-alloy steel that can resist corrosion in the air or in chemically corrosive media. Stainless steel has a beautiful surface and good corrosion resistance. It does not need to undergo surface treatment such as color plating, and can exert the inherent surface properties of stainless steel. A type of steel that is used in many ways, usually called stainless steel. The representative properties are high alloy steel such as 13-chromium steel and 18-chromium-nickel steel.
From the metallographic point of view:Because the stainless steel contains chromium, a very thin chromium film is formed on the surface. In order to maintain the inherent corrosion resistance of stainless steel, the steel must contain more than 12% chromium.
Stainless steel types:Stainless steel can be roughly classified according to use, chemical composition and metallographic structure. Austenitic steels are basically composed of 18% chromium-8% nickel, and the addition of each element varies, and steel grades for various purposes are developed.
Classification by chemical composition: ① CR series: ferrite series, martensite series ② CR-NI series: austenite series, abnormal series, precipitation hardening series.
Classification by metallographic structure:
①. Austenitic stainless steel
②. Ferritic stainless steel
③. Martensitic stainless steel
④. Duplex stainless steel
⑤. Precipitation hardening stainless steel
