ASTM International Standard Specification for Tin Mill Products, Black Plate Electrolytic Chromium-Coated, Single and Double Reduced ASTM A657/A657M-18

This specification covers single- and double-reduced tin mill black plate electrolytically coated with chromium and chromium oxide. The steel shall be furnished in coils and cut lengths for use in manufacture of cans, closures, crowns, and other products. The weights of the total coating which is made up of chromium metal and chromium oxides shall be determined. Single-reduced base steels shall be produced with ground roll finishes (type 7B-A for smooth finish containing fine grit lines and type 7C-A for smooth finish with grit lines), and shot-blasted and/or textured roll finishes (type 5C-A for shot-blasted finish for general applications and type 5D-A for special applications). Double-reduced base steels shall be produced only with ground roll finishes of type 7C-A. The steels shall be furnished with extremely thin oil film on both surfaces.