Mitsubishi Shindoh Co., Ltd.

Jun-Ichi Kumagai

Yoshio Abe

Shunroku Sukumoda

Akira Saito

Shuzo Umezu

Ryo Iino

A Cu&#x2014;Ni&#x2014;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&#x2014;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/mm, and the number of the Ni&#x2014;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/mm, a/b is in a range of 0.5 to 1.5.

Cu&#x2014;Ni&#x2014;Si-based copper alloy sheet having excellent mold abrasion resistance and shear workability and method for manufacturing same

The fatigue resistance characteristics, particularly, fatigue resistance characteristics after retention at 150&#xb0; C. for 1000 hours are improved while maintaining the characteristics in the related art. Provided is a copper alloy sheet having a composition containing 0.2% by mass to 1.2% by mass of Mg, and 0.001% by mass to 0.2% by mass of P, the balance being Cu and unavoidable impurities. When X-ray diffraction intensity of a {110} crystal plane is set as I{110}, and X-ray diffraction intensity of {110} crystal plane of a pure copper standard powder is set as I{110}, a surface crystal orientation of the copper alloy sheet satisfies a relation of 4.0&#x2266;I{110}/I{110}&#x2266;6.0.

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Aizuwakamatsu, Japan

Jun-Ichi Kumagai