Cu-Ni-Si BASED COPPER ALLOY SHEET HAVING HIGH DIE ABRASION RESISTANCE AND GOOD SHEAR PROCESSABILITY AND METHOD FOR PRODUCING SAME

摘要

A Cu-Ni-Si-based copper alloy sheet of the invention has excellent mold abrasion resistance and shear workability while maintaining strength and conductivity, in which 1.0 mass% to 4.0 mass% of Ni is contained, 0.2 mass% to 0.9 mass% of Si is contained, the remainder is made up of Cu and inevitable impurities, the number of Ni-Si precipitate particles having a grain diameter in a range of 20 nm to 80 nm on a surface is in a range of 1.5×10⁶ particles/mm² to 5.0×10⁶ particles/mm², the number of Ni-Si precipitate particles having a grain diameter of greater than 100 nm on the surface is in a range of 0.5×10⁵ particles/mm² to 4.0×10⁵ particles/mm², in a case in which the number of the Ni-Si precipitate particles having a grain diameter in a range of 20 nm to 80 nm in a surface layer that is as thick as 20% of the entire sheet thickness from the surface is represented by a particles/mm², and the number of the Ni-Si precipitate particles having a grain diameter in a range of 20 nm to 80 nm in a portion below the surface layer is represented by b particles/mm², a/b is in a range of 0.5 to 1.5, and the concentration of Si forming a solid solution in crystal grains in an area that is less than 10 µm thickness from the surface is in a range of 0.03 mass% to 0.4 mass%.