270 Copper- and Copper-base Alloys 



TABLE 2 

 GRADE C— 8 PER CENT PHOSPHOR BRONZE" 



Copper, balance; tin, 7.50%; phosphorus, 0.056 7(, 



Property Hard' 



Tensile strength, p.s.i. (000 omitted) 107-99 



Elongation, %ui2in 3-6 



Apparent elastic limit, p.s.i. (000 omitted) 92-84 



Rockwell hardness F, He-m- ball, 60-kg. load 113-110 



Rockwell hardness B, Ji'e-in. ball, 100-kg. load 96-94 



Rockwell hardness G, ffe-in. ball, 150-kg. load 71-73 



Rockwell hardness 15-T, Ji'g-in. ball, 15-kg. load 91 



Rockwell hardness 30-T, He-ia- ball, 30-kg. load 78-79 



Modulus of tensile resHience, in.-lbs. per cu. in 320-270 



Endurance Umit (at 10* reversals):' 



Soft, p.s.i. (000 omitted) 21 



4 B. & S. Nos., hard, p.s.i. (000 omitted) 22 



10 B. & S. Nos., hard, p.s.i. (000 omitted) 24.5 



Young's modulus of elasticity, p.s.i 15,000,000 



Melting point, °F 1877 



Density, lb. per cu. in 0.318 



Coefficient of expansion, per °C. from 25-300°C 0.0000182 



Electrical conductivity, <«« % I.A.C.S. at 68°F 13.00 



Thermal conductivity, «« B.t.u. per sq. ft. per ft. per hr. per °F., 68°F 36.30 



<* AH tests conducted on 0.040-in. stock. 



' 6 B. & S. Nos., hard, 0.015-0.080 mm. grain size at ready-to-finish, respectively, .\pplies to first nine properties. 



!30 

 C20 



no 



100 



90 



: 80 



r 70 



i_ 60 



i 

 ' 50 



:, 40 



30 

 20 







20.7 37.Z 50.0 605 68.6 



Percent Reduction of Area by Rolling 

 2 4 6 8 10 



BSrS Numbers Hard 



Chart 13. — The effect of cold work on the tensile strength and 

 apparent elastic limit of 8 per cent phosphor-bronze strip, previously 

 annealed to two different grain sizes, 0.015 and O.OSO mm. (7.5 % tin, 

 0.056 % phosphorus, balance copper) (0.040-ln. stock). 



20.7 37.2 500 60.5 68.6 



Percent Reduction of Area by Polling 

 2 4 6 8 10 



BSS Numbers Hard 

 Chart 14. — The effect of cold work on the Rockwell hardness and 

 percentage elongation in 2 in. of 8 per cent phosphor-bronze strip, 

 previously annealed to two different grain sizes, 0.015 mm. and 0.080 

 mm. (7.5 % tin, 0.056 % phosphorus, balance copper) (0.040-in. stock). 



