32 



Copper and Copper-base Alloys 



lioo 



!'90 



\ 80 



' 70 

 > 

 ' 60 



50 



40 



30 



20 



10 



CR 400 500 600 700 800 900 1000 1100 1200 1300 1400 

 Annealing Temp.in Deg.F. ( IHr. a+ Temp.) 



Chabt 7. — The effect of annealing on the Rockwell hardness and 

 percentage elongation in 2 in. of gilding-metal strip, previously cold- 

 rolled 6 B. & S. Nos. (50 per cent reduction of area) from two different 

 grain sizes, 0.015 and 0.070 mm. (94.59 % copper) (0.040-in. stock). 



70 



60 



50 



40 



30 



20 



400 500 600 700 800 900 1000 1100 1200 1300 

 Annealing Temp.in Deg.F (iHr. at Temp.) 



Chaet 9. — The effect of annealing on the yield strength of gilding- 

 metal strip, previously cold-rolled 6 B. & S. Nos. (50 per cent reduction 

 of area) from a grain size of 0.070 mm. (94.59 % copper) (0.040-in. 

 stock). 



400 500 600 700 800 900 1000 1100 1200 1300 1400 

 Annealing Temp.in Deg.l^ (l^r. at Temp.) 



Chart 8. — The effect of annealing on the yield strength of gilding- 

 metal strip, previously cold-rolled 6 B. & S. Nos. (50 per cent reduc- 

 tion of area) from a grain size of 0.015 mm. (94.59 % copper) (0.040- 

 in. stock). 



80 

 70 

 60 

 50 

 40 

 30 

 20 



40 50 60 70 80 90 100 



Rockwell HordnessF-'/i6"Ball-60Kg.Load 



5 23 40 58 76 



Rockwell Hardness B-l'ie Ball-lOOKg.Load 



63 68 74 80 85 



Rockwell Hardness I5-T- '/le Ball 15 Kg. Load 



19 31 43 55 67 



Rockwell Hardness 30-T- /le" Ball 30 Kg. Load 



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

 mate tensile strength and percentage elongation of gilding-metal 

 strip when only Rockwell hardness is known. It is accurate for all 

 thicknesses between 0.020 and 0.080 in. within the given limits (94.59 

 per cent copper). 



