Method of producing copper alloy sheet material with excellent strength and conductivity and copper alloy sheet material produced therefrom

A method of producing a copper alloy sheet material, wherein the copper alloy sheet material contains the following component elements:

• nickel (Ni) 0.5 to 1.5% by weight;
• cobalt (Co) 0.3 to 1.5% by weight;
• silicon (Si) 0.35 to 0.8% by weight;
• chromium (Cr) 0.05 to 0.5% by weight;
• a balance amount of copper (Cu);
• and
• inevitable impurities,
• wherein the method comprises:
• melting and casting the above component elements to form an ingot;
• hot-rolling the ingot at 950 to 1040° C.;
• cooling the hot-rolled product;
• cold-rolling the cooled product at a cold reduction rate of 70% or higher to form a copper alloy sheet material;
• performing solid solution heat treatment of the sheet material at 800 to 1040° C. for 20 to 60 seconds;
• and
• performing thermal-mechanical double aging of the solid solution heat treated sheet material,
• wherein the thermal-mechanical double aging includes:
• performing first precipitation of the solid solution heat treated sheet material at 550 to 700° C. for 20 to 60 seconds;
• cold-rolling the first precipitated sheet material at a cold reduction rate of 10 to 50%;
• and
• performing second precipitation of the cold rolled sheet material at 300 to 550° C. for 1 to 24 hours.