Copper alloy and process for producing the same
View Patent ↗A copper alloy consisting of two or more of Cr, Ti and Zr, and the balance Cu and impurities, in which the relationship between the total number N and the diameter X satisfies the following formula (1). Ag, P, Mg or the like may be included instead of a part of Cu. This copper alloy is obtained by cooling a bloom, a slab, a billet, or a ingot in at least in a temperature range from the bloom, the slab, the billet, or the ingot temperature just after casting to 450° C., at a cooling rate of 0.5° C./s or more. After the cooling, working in a temperature range of 600° C. or lower and further heat treatment of holding for 30 seconds or more in a temperature range of 150 to 750° C. are desirably performed. The working and the heat treatment are most desirably performed for a plurality of times. log N ≤0.4742+17.629×exp(−0.1133× X ) (1)
1. A copper alloy consisting of, by mass %, at least two elements selected from the group consisting of 0.01 to 5% of Cr, 0.01 to 5% of Ti and 0.01 to 5% of Zr and the balance Cu and impurities;
wherein the relationship between the total number N of precipitates and intermetallics, having a diameter of not smaller than 1 μm, which are found in 1 mm 2 of the alloy, and the diameter X in μm of the precipitates and the intermetallics having a diameter of not smaller than 1 μm satisfies the following formula (1);
log N≤ 0.4742+17.629×exp(−0.1133× X ) (1)
wherein X=1 when the measured value of the grain size of the precipitates and the intermetallics are 1.0 μm or more and less than 1.5 μm, and X=α (α is an integer of 2 or more) when the measured value is (α−0.5) μm or more and less than (α+0.5) μm.
2. The copper alloy according to claim 1 , wherein the ratio of the maximum value and the minimum value of an average content of at least one alloy element in a micro area is not less than 1.5.
3. The copper alloy according to claim 1 , wherein the copper alloy has a grain size of 0.01 to 35 μm.
4. The copper alloy according to claim 2 , wherein the grain size is 0.01 to 35 μm.
5. A method for producing a copper alloy, comprising cooling a bloom, a slab, a billet, or a ingot obtained by melting a copper alloy according to claim 1 , followed by casting in at least in a temperature range from the bloom, the slab, the billet, or the ingot temperature just after casting to 450° C. at a cooling rate of 0.5° C./s or more, so that the relationship between the total number N and the diameter X satisfies the following formula (1):
log N≤ 0.4742+17.629×exp(−0.1133× X ) (1)
wherein N means the total number of precipitates and intermetallics, having a diameter of not smaller than 1 μm which are found in 1 mm 2 of the alloy; and X means the diameter in μm of the precipitates and the intermetallics having a diameter of not smaller than 1 μm.
6. The method for producing a copper alloy according to claim 5 , further comprising performing working in a temperature range of 600° C. or lower.
7. The method for producing a copper alloy according to claim 6 , further comprising performing heat treatment of holding for 30 seconds or more in a temperature range of 150 to 750° C.
8. The method for producing a copper alloy according to claim 7 , wherein the working in a temperature range of 600° C. or lower and the heat treatment of holding for 30 seconds or more in a temperature range of 150 to 750° C. are performed for a plurality of times.
9. The method for producing a copper alloy according to claim 7 , wherein the working in a temperature range of 600° C. or lower is performed after the final heat treatment.