120 



Table 68 

 MECHANICAL PROPERTIES 



Copper Alloys — Copper-Zinc or Brasses; Copper-Tin or Bronzes 



Compressive Strengths, Brasses: 



Cu 90, Zn 10, cast 21.0 kg/mm 2 or 30,000 lb/in 2 

 Cu 80, Zn 20, cast 27.4 kg/mm 2 or 39,000 lb/in 2 

 Cu 70, Zn 30, cast 42.0 kg/mm 2 or 60,000 lb/in 2 

 Cu 60, Zn 40, cast 52.5 kg/mm 2 or 75,000 lb/in 2 

 Cu 50, Zn 50, cast 77.0 kg/mm 2 or 110,000 lb/in 2 



Modulus of elasticity, — cast brass, — average 9100 kg/mm 2 or 13,000,000 lb/in 2 



Erichsen values: Soft slab, 1.3 mm (0.05 in.) thick, no rolling, depth of impression 13.8 mm (0.55 in.). 



Hard sheet, 1.3 mm, rolled 3S% reduction, depth of impression 7.3 mm (0.29 in.). 



Hard sheet, 0.5 mm, rolled 60% reduction, depth of impression 3.7 mm (0.15 in.). 



Compressive Ultimate Strengths, Cast Bronzes: 



Cu 97.7, Sn 2.3 to 24.0 kg/mm 2 or 34,000 lb/in 2 

 Cu 90, Sn 10 to 39.0 kg/mm 2 or 56.000 lb/in 2 

 Cu 80, Sn 20 to 83.0 kg/mm 2 or 118,000 lb/in 2 

 Cu 70, Sn 30 to 105.0 kg/mm 2 or 150,000 lb/in s 



Specification value, A. S. T. M., B 22-18 T, for specimen = cylinder 645 sq. mm (1 sq. in.) area, 25.4 mm (1 in.) 

 long. 



Cu 80, Sn 20: minimum compressive elastic limit = 17.0 kg/mm 2 or 24,000 lb/in 2 



Modulus of elasticity for bronzes varies from 7000 kg/ mm 2 or 10,000,000 lb/in 2 to 10,000 kg/mm ! or 15,500,000 

 lb/in 2 



* Values marked thus are S. A. E. Spec, values. (See S. A. E. Handbook, Vol. I, p. 13a, rev. December, 1913.) 

 t Red metal. X Low brass or bell metal. 



§ A. S. T. M. Spec. B19-1ST requires B.h.n. of 51-65 kg/mm 2 @ 5000 kg pressure for 70: 30 annealed sheet 

 brass. 



Foot notes to Table 69, Page 121 



* Tensilite, Cu 67, Zn 24, Al 4.4, Mn 3.8, P 0.01 compressive P-limit: 42.2 kg/mm 2 or 60,000 lb/in 2 and 1.33 per 

 cent set for 70.3 kg/mm 2 or 100,000 lb/in 2 load. 



t Compressive P-limit 20.0 to 28.2 kg/mm 2 or 28,500 to 40,000 lb/in 2 



t Compressive ultimate strength 54.5 kg/mm 2 or 77,500 lb/in 2 



§ Compressive P-limit 4.2 kg/mm 2 or 6000 lb/in 2 and 40 per cent set for 70.3 kg/mm 2 or 100,000 lb/in J 



f Modulus of elasticity 9840 kg/mm 2 or 14,000,000 lb/in 2 



1 1 Values are for yield point. ** Minimum values for ingots. 



ft Rolled manganese bronze (U. S. N.) Cu 57 to 60, Zn 40 to 37, Fe max. 2.0, Sn 0.5 to 1.5; 2.9 per cent increase 

 for thickness 25.4 mm (1 in.) and under. 



XX Ni 9 per cent, B.h.n. = 130 as rolled; B.h.n. = 50 as annealed at 930 C. 



U. S. Navy Dept. Spec. 46S 3a, June 1, 1917: German silver Cu 60 to 67, Zn 18 to 22, Ni min. 15, no mechanical 

 requirements. 



For list of 30 German silver alloys, see Braunt, " Metallic Alloys," p. 314, — "best" (Hiorns), " hard Sheffield,' 

 Cu 46, Zn 20, Ni 34. 



§§ Platinoid Cu 60, Zn 24, Ni 14, W 1 to 2; high electric resistance alloy with mechanical properties as nickel bras? 



HII Specification Values, Naval Brass Castings, U. S. Navy, 46B 10b, Dec. 1, 1917 for normal proportions Cu 62, Zn 

 37, Sn 1, min. tensile strength 17.5 kg/mm 2 or 25,000 lb/in 1 with 15 per cent elongation in 50.8 mm (2 in.). 



Smithsonian Tables, 



