Process for high strength, high conductivity copper alloy of Cu-Ni-Si group

1. A process for producing a high strength and high electrical conductivity copper, comprising:

melting and casting raw material to obtain an alloy containing 1-3 wt. % nickel, 0.2-0.7 wt. % silicon, remainder copper and unavoidable impurities;

solution annealing the alloy to produce an annealed alloy having a grain size up to 0.015 mm and an electrical conductivity of up to 26% IACS;

cold deforming the annealed alloy to produce a cold-deformed annealed alloy;

precipitation annealing the cold-deformed alloy at a temperature of 450-500° C. for four to ten hours with a cooling rate of 10-20° C./hour between the annealing temperature and a temperature of approximately 300° C.; and

obtaining a copper alloy having a yield strength of at least 90 ksi and an electrical conductivity of at least 50% IACS.

2. The process of claim 1 , wherein phosphorous up to 0.010 wt. % is added as a deoxidizer during the melting step.

3. The process of claim 1 , wherein the raw material is cast into an ingot.

4. The process of claim 3 , wherein the ingot is hot rolled.

5. The process of claim 1 , wherein the raw material is continuously cast.

6. The process of claim 1 , further comprising the step of cold deforming the alloy prior to solution annealing.

7. The process of claim 1 , wherein the cold deforming comprises cold rolling.

8. The process of claim 1 , wherein the cold deforming comprises drawing.

9. The process of claim 1 , further comprising a first cold deforming step prior to solution annealing with a reduction rate of at least 80% and a second cold deforming step after solution annealing with a reduction rate of 10 to 50%.

10. A process for producing copper alloy with high strength and high conductivity, comprising:

melting and continuously casting raw material to obtain a alloy containing 1-3 wt. % nickel, 0.2 to 0.7 wt. % silicon, remainder copper and unavoidable impurities;

cold deforming the alloy to form a cold-rolled alloy;

solution annealing the cold-rolled alloy to produce an annealed alloy having a grain size up to 0.015 mm and an electrical conductivity of up to 26% IACS;

cold rolling the annealed alloy to form a cold-rolled annealed alloy;

precipitation annealing the cold-rolled annealed alloy at a temperature of 450-500° C. for four to ten hours with a cooling rate of 10-20° C./hour; and

obtaining a copper alloy having a yield strength of at least 90 ksi and an electrical conductivity of at least 50% IACS.

11. A process for producing a high strength and high electrical conductivity copper, comprising:

melting and casting raw material to obtain an alloy containing 1-3 wt. % nickel, 0.2-0.7 wt. % silicon, remainder copper and unavoidable impurities;

cold deforming the alloy with at least 80% reduction;

solution annealing the cold deformed alloy to a grain size of up to 0.015 mm in combination with an electrical conductivity up to 26% IACS;

cold rolling the cold deformed annealed alloy to between 10 and 50% reduction;

precipitation annealing the cold rolled annealed alloy at a temperature of 450-500° C. for four to ten hours with a cooling rate of 10-20° C./hour between the annealing temperature and a temperature of approximately 300° C.; and

obtaining a copper alloy having a yield strength of at least 90 ksi and an electrical conductivity of at least 50% IACS.

12. The process of claim 11 , wherein phosphorous up to 0.010 wt. % is added as a deoxidizer during the melting step.

13. The process of claim 11 , wherein the raw material is cast into an ingot.

14. The process of claim 13 , wherein the ingot is hot rolled.

15. The process of claim 11 , wherein the raw material is continuously cast.

16. The process of claim 11 , wherein the cold deforming comprises cold rolling.

17. A process for producing copper alloy with high strength and high conductivity, comprising:

melting and casting raw material to obtain an alloy containing 1-3 wt. % nickel, 0.2 to 0.7 wt. % silicon, remainder copper and unavoidable impurities;

hot rolling the alloy to form a hot rolled alloy;

cold rolling the hot rolled alloy to form a cold-rolled alloy;

solution annealing the cold-rolled strip to produce an annealed alloy having a grain size up to 0.015 mm and an electrical conductivity of up to 26% IACS;

cold rolling the annealed alloy to form a cold-rolled annealed alloy;

precipitation annealing the cold-rolled annealed alloy at a temperature of 450-500° C. for four to ten hours with a cooling rate of 10-20° C./hour; and

obtaining a copper alloy having a yield strength of at least 90 ksi and an electrical conductivity of at least 50% IACS.