How Hard Is 904L Stainless Steel
904L steel is more expensive and much more complicated to machine because of it’s hardness. Rolex calls 904L stainless steel a “corrosion-resistant superalloy.” 904L differs from 316L because of extra Chromium, Molybdenum, Nickel, and Copper which gives it improved resistance to acids. 316L is considered a tougher, harder, “marine grade” steel, but it does not have luster and acid resistance of 904L.