Nickel containing high copper alloy

Abstract

A high copper alloy with good resistance to stress relaxation at temperatures of up to at least 150° C., consists, by weight, essentially of from 0.8% to 3% of iron, from 0.3% to 2% of nickel, from 0.6% to 1.4% of tin, from 0.005% to 0.35% phosphorous and the remainder copper and inevitable impurities. The alloy has an electrical conductivity in excess of 40% IACS and a yield strength of 70 ksi or higher at final gauge following a relief anneal. Over 75% of an imposed stress remains after exposure to 150° C. for 3000 hours. The combination of good electrical conductivity, high strength and high stress relaxation resistance makes the alloys particularly suitable for under the hood automotive electrical connectors.

We claim:  
     
         1 . A copper alloy consisting, by weight, essentially of: 
 from 0.8% to 3% of iron;    from 0.3% to 2% of nickel;    from 0.6% to 1.4% of tin;    from 0.005% to 0.35% of phosphorous; and    the balance copper and inevitable impurities.    
     
     
         2 . The copper alloy of  claim 1  wherein said iron is present in an amount of from 1% to 2%.  
     
     
         3 . The copper alloy of  claim 2  wherein said iron is present in an amount of from 1% to 1.5%.  
     
     
         4 . The copper alloy of  claim 2  wherein said nickel is present in an amount of from 0.5% to 1.3%.  
     
     
         5 . The copper alloy of  claim 4  wherein said nickel is present in an amount of from 0.5% to 1%.  
     
     
         6 . The copper alloy of  claim 4  wherein said tin is present in an amount of from 0.7% to 1.1%.  
     
     
         7 . The copper alloy of  claim 6  wherein said tin is present in an amount of from 0.8% to 1%.  
     
     
         8 . The copper alloy of  claim 6  wherein said phosphorous is present in an amount of from 0.01% to 0.1%.  
     
     
         9 . The copper alloy of  claim 8  being formed into an electrical connector.  
     
     
         10 . A copper alloy consisting, by weight, essentially of: 
 from 1% to 1.5% of iron;    from 0.5% to 1% of nickel;    from 0.8% to 1% of tin;    from 0.01% to 0.1% of phosphorous; and    the balance copper and inevitable impurities, said alloy having a yield strength of 70 ksi or higher, an electrical conductivity in excess of 40% IACS and sufficient resistance to stress relaxation that over 75% of an imposed stress remains when exposed to temperatures of up to 150° C. for up to 3000 hours.    
     
     
         11 . The copper alloy of  claim 19  formed into an electrical connector.  
     
     
         12 . A method for the manufacture of a copper alloy having an electrical conductivity in excess of 40% IACS and sufficient resistance to stress relaxation that over 75% of an imposed stress remains when exposed to temperatures of up to 150° C. for up to 3000 hours, comprising the steps of: 
 (a) casting a copper base alloy containing, by weight, 0.8% to 3% of iron, 0.3% to 2% of nickel, 0.6% to 1.4% of tin, 0.005% to 0.35% of phosphorous and the balance copper and inevitable impurities;  
 (b) hot working said copper alloy at a temperature in excess of 700° C. thereby forming a slab:  
 (c) cold working said slab to a first desired thickness thereby forming a strip;  
 (d) annealing said strip at a temperature of between 500° C. and 650° C. for from 2 hours to 6 hours;  
 (e) cold working said strip to an intermediate thickness;  
 (f) annealing said strip at a temperature of between 450° C. and 600° C. for from one to six ours;  
 (g) cold working said strip to a desired final gauge; and  
 (f) relief annealing said strip at final gauge at a temperature of between 200° C. and 350° C. for from thirty minutes to six hours.  
 
     
     
         13 . The method of  claim 12  wherein said hot working occurs at a temperature of between 750° C. and 950°.  
     
     
         14 . The method of  claim 13  including the additional stirp of removing surface oxides from said slab following hot working.  
     
     
         15 . The method of  claim 14  wherein said intermediate thickness is selected so that said strip has a yield strength of 70 ksi or higher following said relief anneal step (f).  
     
     
         16 . The method of  claim 15  wherein said relief anneal is at a temperature of between 250° C. and 325° C. for a time of from one to three hours.  
     
     
         17 . The method of  claim 16  including forming said copper alloy at desired final gauge into an electrical connector.  
     
     
         18 . The method of  claim 14  wherein said intermediate thickness is selected so that said strip has a yield strength of 75 ksi or higher following said relief anneal step (f).  
     
     
         19 . The method of  claim 18  wherein said relief anneal is at a temperature of between 250° C. and 325° C. for a time of from one to three hours.  
     
     
         20 . The method of  claim 19  including forming said copper alloy at desired final gauge into an electrical connector.