204 



Copper and Copper-base Alloys 



TABLE 6 

 18 PER CENT NICKEL SILVER 



Generai, Data" — Strip 

 Copper, 62.05%; nickel, 18.40%; zinc, 19.36%; manganese, 0.12%; lead, 0.004%; iron, 0.07% 



Property 



Tensile strength, p.s.i. (000 omitted) 



0.10 % proof strength, p.s.i. (000 omitted) 



Limit of proportionality, p.s.i. (000 omitted) 



Elongation, % in 2 in 



Reduction of area, % 



Rockwell hardness B, Ke-™. ball, 100-kg. load . . . . 



Rockwell hardness E, J^-in. ball, 100-kg. load 



Diamond pyramid hardness, 10-kg. load 



Erichsen value, mm 



BrineU hardness, 10-kg., 1-mm. ball 



Shore Scleroscope M. H 



S. & S., Shore Scleroscope U. H. <& self-recorder 



Specific gravity 



Density, lb. per cu. in 



Coefficient of thermal expansion, X 10~*: 



At 0-100°C 



At 0-200°C 



At 0-300°C 



At 0-400°C 



Thermal conductivity: 



At 70°F., B.t.u. per sq. ft. per ft. per hr. per °F.. 



At 400°F., B.t.u. per sq. ft. per ft. per hr. per °F 

 Temperature coefficient of thermal conductivity . . . . 



Specific resistance, microhms-cm.' at 20°C 



Melting point, °F 



Modulus of elasticity, p.s.i 



Hard'' 



100 

 91 



94 

 112 

 209 



184 



58 



39 



3.719 



Soft' 



14.8 

 15.4 

 16.0 

 16.8 



13.07 

 15.73 

 0.00114 

 27.55 



2010 

 18,000,000 



<» Based on data by Cook/^^' 



* Refers to strip cold-rolled 60 % (redu 



^ Refers to a 1450°F. anneal for 2 hr. 



nion in thickness) from a ready-to-finish anneal at 1450''F. for 2 hr. 



120 



no 



100 

 90 



so 



A 70 



\ 60 



Q. 



:S 50 



o 



§ 40 



30 

 20 



10 20 30 40 5Q 60 70 80 90 

 Percent Reduction in Thickness 



Chart 41. — The effect of cold rolling on the tensile strength, proof 

 strength, and proportional limit of IS per cent nickel-silver strip 

 (18.40 % nickel, 62.05 % copper, balance zinc) previously annealed at 

 1450°F. according to Cook.'26> 



240 



220 



200 



180 

 « 160 

 I 140 



1^120 



c 

 "OIOO 



o 

 ^ 80 



60 



40 



20 







10 20 30 40 50 60 70 80 90 

 Percent Reductfon in Thickness 



Chaht 42. — The effect of cold rolling on the hardness of 18 per cent 

 nickel-silver strip (18.40 % nickel, 62.05 % copper, balance zinc) 

 previously annealed at 1450°F. according to Cook.'^e) 



