Copper alloy and method of producing same

Abstract

To obtain a copper alloy having a tensile strength of 700 N/mm 2 or more and a conductivity of 60% IACS or more, a copper alloy of the present invention comprises from 0.8 mass % to 1.8 mass % of Co, from 0.16 mass % to 0.6 mass % of Si, and the balance of Cu and unavoidable impurities, in which a mass ratio of Co to Si (Co/Si) is between 3.0 and 5.0; a size of inclusions to be precipitated in the copper alloy is 2 μm or less; and a total volume of the inclusions having a size of between 0.05 μm and 2 μm in the copper alloy is 0.5 vol % or less.

1 . A copper alloy comprising from 0.8 mass % to 1.8 mass % of Co, from 0.16 mass % to 0.6 mass % of Si, and the balance of Cu and unavoidable impurities, wherein
 a mass ratio of Co to Si (Co/Si) is between 3.0 and 5.0;   a size of inclusions to be precipitated in the copper alloy is 2 μm or less; and   a total volume of the inclusions having a size of between 0.05 μm and 2 μm in the copper alloy is 0.5 vol % or less.   
     
     
         2 . A copper alloy according to  claim 1 , further comprising from 0.1 mass % to 1.0 mass % of Zn. 
     
     
         3 . A copper alloy according to  claim 1 , further comprising from 0.01 mass % to 0.2 mass % of one or more elements selected from the group consisting of Fe, Ni, P, Sn, Mg, Zr, Cr, and Mn in total. 
     
     
         4 . A copper alloy according to  claim 1 , wherein the copper alloy has an O2 content of 10 ppm or less and an H2 content of 1 ppm or less. 
     
     
         5 . A method of producing a copper alloy, comprising the steps of:
 (a) melting a copper alloy raw material including from 0.8 mass % to 1.8 mass % of Co, from 0.16 mass % to 0.6 mass % of Si, and the balance of Cu and unavoidable impurities and having a mass ratio of Co to Si (Co/Si) is between 3.0 and 5.0 to form an ingot, and rolling the ingot;   (b) carrying out solution treatment involving heating the rolled material to between 700° C. and 1,000° C. and quenching;   (c) carrying out aging treatment by heating an alloy material subjected to the solution treatment at between 400° C. and 600° C. for 2 hours to 8 hours;   (d) cooling the alloy material subjected to the aging treatment to at least 380° C. at a cooling rate of between 10° C./h and 50° C./h; and   (e) finishing the cooled alloy material by cold rolling.   
     
     
         6 . A method of producing a copper alloy according to  claim 5 , wherein the copper alloy raw material further comprises from 0.1 mass % to 1.0 mass % of Zn. 
     
     
         7 . A method of producing a copper alloy according to  claim 5 , wherein the copper alloy raw material further comprises from 0.01 mass % to 0.2 mass % of one or more elements selected from the group consisting of Fe, Ni, P, Sn, Mg, Zr, Cr, and Mn in total. 
     
     
         8 . A method of producing a copper alloy according to  claim 5 , wherein the copper alloy raw material has an O 2  content of 10 ppm or less and an H 2  content of 1 ppm or less.