Copper alloy sheet and method of manufacturing copper alloy sheet

A copper alloy sheet which is manufactured by a manufacturing process including a finish cold-rolling process of cold-rolling a copper alloy material,

• wherein an average grain size of the copper alloy material is 2.0 μm to 7.0 μm,
• a sum of an area ratio of a β phase and an area ratio of a γ phase in a metallographic structure of the copper alloy material is 0% to 0.9%,
• the copper alloy sheet contains 28.0 mass % to 35.0 mass % of Zn, 0.15 mass % to 0.75 mass % of Sn, 0.005 mass % to 0.05 mass % of P, either or both of 0.005 mass % to 0.05 mass % of Co and 0.5 mass % to 1.5 mass % of Ni, and a balance consisting of Cu and unavoidable impurities, and
• a Zn content [Zn] (mass %) and a Sn content [Sn] (mass %) satisfy relationships of 44≧[Zn]+20×[Sn]≧37 and 32≦[Zn]+9×([Sn]−0.25)1/2≦37.

A copper alloy sheet which is manufactured by a manufacturing process including a finish cold-rolling process of cold-rolling a copper alloy material,

• wherein an average grain size of the copper alloy material is 2.0 μm to 7.0 μm,
• a sum of an area ratio of a β phase and an area ratio of a γ phase in a metallographic structure of the copper alloy material is 0% to 0.9%,
• the copper alloy sheet contains 28.0 mass % to 35.0 mass % of Zn, 0.15 mass % to 0.75 mass % of Sn, 0.005 mass % to 0.05 mass % of P, 0.003 mass % to 0.03 mass % of Fe, and a balance consisting of Cu and unavoidable impurities, and
• a Zn content [Zn] (mass %) and a Sn content [Sn] (mass %) satisfy relationships of 44≧[Zn]+20×[Sn]≧37 and 32≦[Zn]+9×([Sn]−0.25)1/2≦37.

A copper alloy sheet which is manufactured by a manufacturing process including a finish cold-rolling process of cold-rolling a copper alloy material,

• wherein an average grain size of the copper alloy material is 2.0 μm to 7.0 μm,
• a sum of an area ratio of a β phase and an area ratio of a γ phase in a metallographic structure of the copper alloy material is 0% to 0.9%,
• the copper alloy sheet contains 28.0 mass % to 35.0 mass % of Zn, 0.15 mass % to 0.75 mass % of Sn, 0.005 mass % to 0.05 mass % of P, 0.003 mass % to 0.03 mass % of Fe, either or both of 0.005 mass % to 0.05 mass % of Co and 0.5 mass % to 1.5 mass % of Ni, and a balance consisting of Cu and unavoidable impurities, and
• a Zn content [Zn] (mass %) and a Sn content [Sn] (mass %) satisfy relationships of 44≧[Zn]+20×[Sn]≧37 and 32≦[Zn]+9×([Sn]−0.25)1/2≦37, and a Co content [Co] (mass %) and a Fe content [Fe] (mass %) satisfy a relationship of [Co]+[Fe]≦0.04.