Abstract: A copper based alloy consists essentially, by weight %, of 15 to 35% Zn, 7 to 14% Ni, 0.1 to 2% or less Mn, 0.01 to 0.5% Fe, 0.0005 to 0.1% P, at least one or two elements selected from the group consisting of 0.001 to 0.9% Si, 0.0003 to 0.02% Pb, and 0.0003 to 0.01% C, the total content of the selected at least two elements being limited to a range of 0.0006 to 0.9%, and the balance of Cu and inevitable impurities. The copper based alloy has excellent blankability as well as good corrosion resistance and high strength.

Abstract: There is provided a copper alloy sheet for forming a connector, having a chemical composition consisting essentially of:Mg: 0.3-2% by weight;P: 0.001-0.02% by weight;C: 0.0002-0.0013% by weight;O: 0.0002-0.001% by weight; andCu and inevitable impurities: the balance. The copper alloy sheet has a structure that fine particles of oxides including Mg oxide having a particle size of not more than 3 .mu.m are evenly dispersed in a matrix of the copper alloy sheet. The copper alloy sheet is excellent not only in tensile strength, elongation, electric conductivity and spring limit value before forming, but also in spring limit value after forming, and high-temperature creep strength.

Abstract: A copper based alloy for use as a material for electrical and electronic parts has a chemical composition by weight, of 0.5 to 3% Ni, 0.1 to 0.9% Sn, 0.08 to 0.8% Si, 0.1 to 3 Zn, 0.007 to 0.25% Fe, 0.001 to 0.2% P, 0.001 to 0.2% Mg, 0.0001 to 0.001% C, and if required, further containing 0.001 to 0.3% at least one element of Cr and Zr, and the balance being Cu and inevitable impurities. The obtained copper alloy is excellent in electric conductivity, solder-exfoliation resistance when bent, high-temperature creep strength, and migration resistance, while being superior in hot workability and blankability to the conventional copper based alloy.