Extra-fine copper alloy wire, extra-fine copper alloy twisted wire, extra-fine insulated wire, coaxial cable, multicore cable and manufacturing method thereof

摘要

An extra-fine copper alloy wire has: a wire diameter of 0.010 to 0.025 mm; 1 to 3 weight % of silver (Ag), and a balance consisting copper (Co) and an inevitable impurity; a tensile strength of not less than 850 MPa; an electrical conductivity of not less than 85% IACS; an elongation of 0.5 to 3.0%; and a lowering rate in tensile strength of not more than 2%. The lowering rate is represented by [(1−σ_h1/σ_h0)×100%] where σ_h1 is a tensile strength of the wire measured after a heat treatment under conditions of a heating temperature of not more than 350° C. and a heating time of not more than 5 seconds, and σ_h0 is a tensile strength of the wire measured before the heat treatment.