304 stainless steel, steel number: 0Cr18Ni9 There are many ways to classify stainless steel. According to the main chemical composition is divided into chromium stainless steel, chromium nickel stainless steel and chromium manganese nitrogen stainless steel. 0Cr18Ni9 is chromium-nickel stainless steel. Divided into acid-resistant stainless steel and heat-resistant stainless steel according to performance characteristics. 0Cr18Ni9 belongs to acid-resistant stainless steel. Metallographic structure is divided into: austenitic stainless steel, ferritic stainless steel, martensitic stainless steel, duplex stainless steel, precipitation hardening stainless steel, etc. 0Cr18Ni9 belongs to austenitic stainless steel. There are some less commonly used classification methods that are not listed one by one. In general, it is most commonly used and classified by the metallurgical organization. So generally speaking 0Cr18Ni9 belongs to austenitic stainless steel.