The rust and corrosion resistance of stainless steel is due to the formation of a chromium-rich oxide film (passivation film) on its surface. This rust resistance and corrosion resistance are relative. Tests show that the corrosion resistance of steel in weak media such as atmosphere and water and in oxidizing media such as nitric acid increases with the increase of chromium water content in steel. When the chromium content reaches a certain percentage, the corrosion resistance of steel occurs.
According to the structure at room temperature, there are martensitic, austenitic, ferritic and duplex stainless steels; according to the main chemical components, they can be basically divided into two major systems: chromium stainless steel and chromium-nickel stainless steel; There are nitric acid-resistant stainless steel, sulfuric acid-resistant stainless steel, seawater-resistant stainless steel, etc., which can be divided into pitting corrosion-resistant stainless steel, stress corrosion-resistant stainless steel, intergranular corrosion-resistant stainless steel, etc. according to the type of corrosion resistance.
Magnetic stainless steel, free cutting stainless steel, low temperature stainless steel, high strength stainless steel, etc. Due to its excellent corrosion resistance, formability, compatibility and toughness in a wide temperature range, stainless steel has been widely used in heavy industry, light industry, daily necessities industry and building decoration industries. .