Commonly used stainless steel materials are: 201, 202, 301, 303, 304, 304L, 316, 316L, 321, 310S, 401, 409, 410, 420J1, 420J2, 430, 439, 443, 444.

In layman’s terms, stainless steel is not easy to rust. In fact, some stainless steel have both rust resistance and acid resistance (corrosion resistance). Stainless steel and corrosion resistance is due to the formation of chromium-rich oxide film (passivation film) on its surface. This stainlessness and corrosion resistance are relative. Tests show that the corrosion resistance of steel in weak media such as the atmosphere and water and oxidizing media such as nitric acid increases with the increase of the chromium water content in the steel. When the chromium content reaches a certain percentage, the corrosion resistance of the steel occurs Sudden change, that is, from easy to rust to hard to rust, from non-corrosion resistance to corrosion resistance. There are many ways to classify stainless steel.

Classified according to the structure at room temperature, there are martensite, austenite, ferrite and duplex stainless steel; according to the main chemical composition, it 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. Because of its excellent corrosion resistance, formability, compatibility, and strength and toughness in a wide temperature range, stainless steel has been widely used in heavy industry, light industry, daily necessities industry, building decoration and other industries .