Copper alloy having the basic composition Cu—Zn—Sn contains 23-28 wt % Zn and 0.3-1.8 wt % Sn and satisfies the relation 6.00.25X+Y8.5 (where X is the addition of Zn in wt % and Y is the addition of Sn in wt %). The alloy is cast into an ingot by melting and cooling over the range from the liquidus line to 600 C. at a rate of at least 50 C./min; the ingot is hot rolled at a temperature not higher than 900 C. and then subjected to repeated cycles of cold rolling and annealing at 300-650 C. to control the size of crystal grains, thereby producing a rolled strip having a 0.2% yield strength of at least 600 N/mm², a tensile strength of at least 650 N/mm², an electrical conductivity of at least 20% IACS, a Young's modulus of no more than 120 kN/mm² and a percent stress relaxation of no more than 20%.