COPPER ALLOY SHEET

摘要

Cu-Ni-Sn-P copper alloy sheets of specified compositions. (1) In one form of copper alloy sheet, the electric conductivity is 32% IACS or greater. Along the direction parallel to rolling direction, the stress relaxation coefficient is 15% or below. The 0.2% proof strength is 500 MPa or greater, and the elongation is 10% or greater. (2) In another form, not only the X-ray diffracted intensity ratio I(200)/I(220) on the surface of the copper alloy sheet is regulated to a given level or below but also the crystal grain diameter is reduced to thereby decrease the anisotropy of stress relaxation resistance property. (3) In a further form, the structure of the copper alloy sheet is caused to be an aggregate structure such that the orientation distribution density in B-orientation and the sum of orientation distribution densities in B-orientation, S-orientation and Cu-orientation fall within specified ranges to thereby attain an enhancement of bending workability. (4) In still a further form, the dislocation density determined as the quotient of the half-value breadth of X-ray diffracted intensity peak from the {200} face of the copper alloy sheet surface divided by the height of the peak is a given level or greater to thereby attain an enhancement of press punchability. These Cu-Ni-Sn-P copper alloy sheets excel in the performance demanded for terminal/connector. Further, they excel in strength-ductility balance (1), or are satisfactory in the stress relaxation resistance property along the direction perpendicular to rolling direction (2), or excel in bending workability (3), or excel in press punchability (4).