Copper alloy sheet material and method for producing copper alloy sheet material
A copper alloy sheet material which contains 0.5 to 2.5% by mass of Ni, 0.5 to 2.5% by mass of Co, 0.30 to 1.2% by mass of Si and 0.0 to 0.5% by mass of Cr, the balance being Cu and unavoidable impurities. The material fulfills the relationships 1.0≤I {200}/I 0 {200}≤5.0 and 5.0 μm≤GS≤60.0 μm, and these have the relationship (Equation 1): 5.0≤{(I {200}/I 0 {200})/GS}×100≤21.0, in which the I {200} represents an X-ray diffraction intensity of a {200} crystal plane, the I 0 {200} represents an X-ray diffraction intensity of a {200} crystal plane of standard pure copper powder, and the GS (μm) represents an average crystal grain size. An electrical conductivity is 43.5% to 55.0% IACS and 0.2% yield strength is 720 to 900 MPa.
1. A copper alloy sheet material comprising 0.5 to 2.5% by mass of Ni, 0.5 to 2.5% by mass of Co, 0.30 to 1.2% by mass of Si and 0.0 to 0.5% by mass of Cr, the balance being Cu and unavoidable impurities, wherein the copper alloy sheet material fulfills the relationships 1.0≤I {200}/I 0 {200}≤5.0 and 5.0 μm≤GS≤60.0 μm, and these have the relationship (Equation 1): 5.0≤{(I {200}/I 0 {200})/GS}×100≤21.0, in which the I {200} represents an X-ray diffraction intensity of a {200} crystal plane on the plate surface, the I 0 {200} represents an X-ray diffraction intensity of a {200} crystal plane of standard pure copper powder, and the GS (μm) represents an average crystal grain size as determined by a cutting method of JIS H 0501, wherein the copper alloy sheet material has an electrical conductivity of 43.5% IACS or more and 55.0% IACS or less, and 0.2% yield strength of 720 MPa or more and 900 MPa or less, wherein according to a press formability test, an average of 100 sag lengths is less than plate thickness×0.05, wherein the press formability test includes 100 press tests of punching sheet material into a circle shape having a radius of 1.0 mm.
2. The copper alloy sheet material according to claim 1 , further comprising a total of up to 0.5% by mass of one or more elements selected from the group consisting of Mg, Sn, Ti, Fe, Zn and Ag.
3. A method for producing a copper alloy sheet material according to claim 1 , comprising the successive steps of:
melting and casting a raw material of a copper alloy comprising 0.5 to 2.5% by mass of Ni, 0.5 to 2.5% by mass of Co, 0.30 to 1.2% by mass of Si, and 0.0 to 0.5% by mass of Cr, the balance being Cu and unavoidable impurities;
hot-rolling the material while lowering the temperature from 950° C. to 400° C.;
cold-rolling the material at a rolling rate of 30% or more;
pre-annealing the material by carrying out a heat treatment for the purpose of deposition, at a heating temperature of 350 to 500° C. for 5.0 to 9.5 hours (calculation formula (Equation 2): t=38.0×exp (−0.004 K) is satisfied between the time of the pre-annealing step (t) and a temperature K (° C.);
cold-rolling the material at a rolling rate of 70% or more;
solutionizing the material at a heating temperature of 700 to 980° C.;
aging-treating the material at 350 to 600° C.; and
finish-cold-rolling the material at a rolling rate of 10% or more and 40% or less,
wherein the producing conditions are adjusted such that calculation formula (Equation 3): K=4.5×(I {200}/I 0 {200}×exp (0.049a)+76.3) is satisfied among a degree of processing a in the finish cold rolling step, I {200}/I 0 {200} after the finish cold rolling step, and a temperature K (° C.) in the pre-annealing step.
4. The method for producing the copper alloy sheet material according to claim 3 , wherein the copper apply sheet material further comprises a total of up to 0.5% by mass of one or more elements selected from the group consisting of Mg, Sn, Ti, Fe, Zn and Ag.