Claims
- 1. A copper alloy having improved stress relaxation resistance, said copper alloy consisting essentially of:from 1.8 to 3.0 weight percent iron; from 0.01 to 1.0 weight percent zinc; from 0.001 to 0.25 weight percent phosphorous; from greater than 0.11 to 0.35 weight percent of free magnesium; less than 0.2 weight percent titanium less than 0.1 weight percent tin; and the balance copper and unavoidable impurities whereby said copper alloy is substantially free of magnesium phosphide inclusions and has an electrical conductivity of greater than or equal to 60% IACS.
- 2. The copper alloy of claim 1 wherein said iron content is, by weight, from 2.0% to 2.7%.
- 3. The copper alloy of claim 2 wherein said magnesium content is, by weight, from 0.11% to 0.30%.
- 4. The copper alloy of claim 3 wherein said zinc content is, by weight, from 0.01% to 0.50%.
- 5. The copper alloy of claim 4 wherein said alloy has a resistance to stress relaxation in a direction transverse to a rolling direction that is within about 3% of a resistance to stress relaxation in a direction longitudinal to said rolling direction when exposed to 105° C. for 3000 hours following 30% cold rolling and annealing at 300° C. for 4 hours.
- 6. The copper alloy of claim 4 wherein at least a portion of said iron is replaced with cobalt on a 1:1, by weight, basis.
- 7. A copper alloy having improved stress relaxation resistance, said copper alloy consisting essentially of:from 2.1 to 2.6 weight percent iron; from 0.05 to 0.25 weight percent zinc; from 0.01 to 0.09 weight percent phosphorous; from greater than 0.12 to 0.25 weight percent of free magnesium; less than 0.2 weight percent titanium; less than 0.1 weight percent tin; and the balance copper and unavoidable impurities whereby said copper alloy is substantially free of magnesium phosphide inclusions and has an electrical conductivity greater than or equal to 60% IACS.
- 8. The copper alloy of claim 7 wherein said alloy has a resistance to stress relaxation in a direction transverse to a rolling direction that is within about 3% of a resistance to stress relaxation in a direction longitudinal to said rolling direction when exposed to 105° C. for 3000 hours following 30% cold rolling and annealing at 300° C. for 4 hours.
- 9. The copper alloy of claim 7 wherein at least a portion of said iron is replaced with cobalt on a 1:1, by weight, basis.
CROSS REFERENCE TO RELATED PATENT APPLICATION
This patent application claims priority to United States Provisional Patent Application Ser. No. 60/214,211 that was filed on Jun. 26, 2000. The subject matter of that provisional patent application is incorporated by reference in its entirety herein.
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