International Stainless Steel Labeling Method

The American Iron and Steel Institute uses three digits to label various standard grades of malleable stainless steel. Among them:
① Austenitic stainless steel with 200 and 300 series of digital marks.
② Ferrite and martensitic stainless steel are represented by 400 series numbers. For example, some of the more common austenitic stainless steels are labeled 201, 304, 316, and 310.
③ Ferritic stainless steel is marked with 430 and 446, martensitic stainless steel is marked with 410, 420 and 440C, biphase (austenite-ferrite).
Stainless steel, precipitation-hardened stainless steel and high alloys with an iron content of less than 50% are usually named by patent names or trademarks.