Copper alloy sheet material having a low young's modulus and method of producing the same

Abstract

{Problems} To provide a copper alloy material, having a low Young's modulus that is required of electrical or electronic parts, such as connectors. {Means to solve} A copper alloy sheet material for electrical or electronic parts, having an alloy composition containing any one or both of Ni and Co in an amount of 0.5 to 5.0 mass % in total, and Si in an amount of 0.2 to 1.5 mass %, with the balance being Cu and inevitable impurities, wherein the copper alloy sheet material has a 0.2% proof stress in the rolling direction of 500 MPa or more, an electrical conductivity of 30% IACS or more, a Young's modulus of 110 GPa or less, and a factor of bending deflection of 105 GPa or less.

1 - 9 . (canceled) 
     
     
         10 . A copper alloy sheet material for electrical or electronic parts, having an alloy composition containing any one or both of Ni and Co in an amount of 0.5 to 5.0 mass % in total, Si in an amount of 0.2 to 1.5 mass %, optionally Cr in an amount of 0.05 to 0.5 mass %, and optionally at least one selected from the group consisting of Zn, Sn, Mg, Ag, Mn, and Zr in an amount of 0.01 to 1.0 mass % in total, with the balance being Cu and inevitable impurities,
 wherein the copper alloy sheet material has a 0.2% proof stress in the rolling direction of 500 MPa or more, an electrical conductivity of 30% IACS or more, a Young's modulus of 110 GPa or less, and a factor of bending deflection of 105 GPa or less.   
     
     
         11 . The copper alloy sheet material for electrical or electronic parts according to  claim 10 , wherein the copper alloy sheet material has an area ratio of (1 0 0) plane oriented toward the rolling direction, which is obtained by analyzing the copper alloy sheet material with EBSD, is 30% or more. 
     
     
         12 . The copper alloy sheet material for electrical or electronic parts according to  claim 10 , wherein the copper alloy sheet material has an area ratio of (1 1 1) plane oriented toward the rolling direction, which is obtained by analyzing the copper alloy sheet material with EBSD, is 15% or less. 
     
     
         13 . The copper alloy sheet material for electrical or electronic parts according to  claim 11 , wherein the copper alloy sheet material has an area ratio of (1 1 1) plane oriented toward the rolling direction, which is obtained by analyzing the copper alloy sheet material with EBSD, is 15% or less. 
     
     
         14 . A connector, which is composed of the copper alloy sheet material for electrical or electronic parts according to  claim 10 . 
     
     
         15 . A method of producing the copper alloy sheet material for electrical or electronic parts according to  claim 10 , containing, in this order, the steps of:
 subjecting a copper alloy to give the alloy composition to casting;   hot-rolling;   cold-rolling 1 at a rolling ratio of 70% or higher;   intermediate annealing at 300 to 800° C. for 5 seconds to 2 hours;   cold-rolling 2 at a rolling ratio of 3 to 60%;   solution heat treatment at 600 to 1,000° C. for 5 seconds to 300 seconds;   aging heat treatment at 400 to 600° C. for 0.5 hours to 8 hours;   finish cold-rolling at a working ratio of 50% or less; and   low-temperature annealing at 300 to 700° C. for 10 seconds to 2 hours,   wherein the method of producing further contains, conducting at least any one or both of the following steps [1] and [2]:   [1] slowly cooling at a cooling speed of 5 K/second or less to a temperature of 350° C., after the hot-rolling; and   [2] carrying out the intermediate annealing and the cold-rolling 2, repeatedly two times or more.