300 and 400 Quality Series
300 Series Austenitic Alloys:
304, 309, 310, 316, 321 series stainless steels contain chromium and nickel. It is not possible to apply heat treatment and they do not hold magnets. They have a high shape-taking ability.
400 Series Ferritic Alloys: 430, 409, 429, Stainless steels in this series contain chromium. They can be magnetized but not heat treated.