IMPROVING FORMABILITY OF WROUGHT COPPER-NICKEL-TIN ALLOYS

摘要

Disclosed are processes for improving the formability of a copper-nickel-tin alloy having a 0.2% offset yield strength that is above 115 ksi. The alloy includes about 14.5 to about 15.5 wt% nickel, about 7.5 to about 8.5 wt% tin, and the remaining balance is copper. The copper-nickel-tin alloy is mechanically cold worked to undergo between 5% and 15% plastic deformation. The alloy is then heat treated at elevated temperatures of about 450°F to about 550°F for a period of about 3 hours to about 5 hours. The alloy is then subsequently mechanically cold worked again to undergo between 4% and 12% plastic deformation. The alloy is then further heated to an elevated temperature of about 700°F to about 850°F for a period between about 3 minutes and about 12 minutes to relieve stress. The resulting alloy has a combination of good formability ratio and good yield strength.