MANUFACTURE OF COPPER ALLOY AND COPPER ALLOY MATERIAL FOR RADIATOR PLATE

PURPOSE:To manufacture the Cu alloy material having excellent stress corrosion cracking resistance, strength, formability, solderability, etc., as a radiator plate material for joining with a tank made of resin by subjecting a cold rolled sheet of a Cu-Zn-Ni-Si series alloy having specified compsn. to final annealing and furthermore subjecting it to cold rolling at a specified draft. CONSTITUTION:As a radiator plate 7 used for a radiator tank 6 made of resin, a cold rolled sheet having intermediate sheet thickness of a Cu alloy constituted of, by weight, 5 to 30% Zn, 0.1 to 10% Ni, 0.01 to 3% Si and the balance Cu or a Cu alloy moreover contg., as the elements for improving strength, 0.001 to 2.0% of one or more kinds among Al, Fe, Pb, As, Sb, B, Co, Cr, Mn, Te, In, Ti, Zr, Hf, Be, Mg, Ag, Cd and Ge is subjected to final annealing and is furthermore subjected to final cold rolling at 3 to 20% draft. The Cu alloy sheet as a radiator plate having