1.1 This International Standard applies to cold-reduced carbon steel sheet and corresponding hardness requirements. It is suitable for applications where the surface is of prime importance. 1.2 The fabrication limits of cold-reduced carbon steel sheet according to hardness requirements are dependent on the specific range of hardness specified or agreed to. It is produced in thicknesses of 0,36 mm and above (commonly produced up to 3 mm) and in widths of 600 mm and over in coils and cut lengths. The hardness is commonly reported as Rockwell B (HRB). 1.3 The following are common hardness ranges (see 5.6): ⎯ CRH-50 Rockwell B 50 to 70; ⎯ CRH-60 Rockwell B 60 to 80; ⎯ CRH-70 Rockwell B 70 to 90; ⎯ CRH-NN Any Rockwell B range of 20 points up to and including HRB 90 maximum (designated minimum of specified range will be shown). NOTE By agreement between the supplier and purchaser, Rockwell ranges less than 20 points can be specified. 1.4 Cold-reduced sheet less than 600 mm wide can be slit from wide sheet and will be considered as sheet. 1.5 This International Standard does not cover commercial quality or drawing qualities (covered in ISO 3574) and cold-reduced carbon steel strip.