Abstract: 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 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.

Abstract: 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 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.