230 



Copper and Copper-base Alloys 



CR 700 800 900 lOOO 1100 1200 1300 1400 1500 1600 

 Annealing Temp, in Deg.K(lHr a\ Temp.) 

 Cs-iRT 9. — The effect of annealing on the yield strength of 70-30 

 cupro-nickel strip, pre\'iously cold-rolled 6 B. & S. Nos. (50 per cent 

 reduction of area) from a grain size of 0.070 mm. (68.94 % copper, 

 29.61 % nickel) (0.040-in. stock). 



90 

 80 



'C 60 



a. 

 J3 50 



?30 



<^ 20 



E 10 



30 



40 

 Rockwel 



50 60 70 80 90 



Hardness /le'Ball B 100 Kg. Load 

 74 80 86 91 97 - 



Rockwell Hardness /le" Ball F 60 Kg. Load 

 71 74 77 80 84 87 90 



Rockwell Hardness V Ball 15 T 15 Kg. Load 

 36 43 50 57 61 70 76 



Rockwell Hardness '/ib" Ball 30T 30 Kg. Load 

 Chart 10. — This chart can be employed to determine the approxi- 

 mate tensile strength and percentage elongation of 70-30 cupro-nickel 

 strip (68.94 % copper, 29.61 % nickel) when only Rockwell hardness is 

 known. It is accurate for all thicknesses between 0.020 and O.OSO in. 

 within the given limits. 







0.002 



0.004 0.006 0.008 0.010 

 Sirain. inches per Inch 

 Chart 11. — The effect of cold rolling on the stress-strain charac- 

 teristics of 70-30 cupro-nickel strip (0.040 in. thick) having a ready- 

 to-finish grain size of 0.015 mm.; 5,000-lb. capacity hydraulic testing 

 machine and Templin automatic extensometer accurate to 0.00001 

 in. used. (68.94 % copper, 29.61 % nickel.) 



0.002 



0.010 



0.004 0.006 0.008 

 Strain, Inches per Inch 

 Chart 12. — The effect of cold rolling on the stress-strain charac- 

 teristics of 70-30 cupro-nickel strip (0.040 in. thick) having a ready-to- 

 finish grain size of 0.070 mm.; 5,000-lb. capacity hydraulic testing 

 machine and Templin automatic extensometer accurate to 0.00001 

 in. used (68.94 % copper, 29.61 % nickel). 



