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BELL SYSTEM TECHNICAL JOURNAL 



bronze has still greater wear resistance than brass or nickel silver and 

 superior spring properties. 



The chemical compositions of brass, nickel silver, and phosphor 

 bronze spring materials used for telephone apparatus are shown in 

 Table 1 and the mechanical properties are given in Table 2. The 

 range of tensile strength and hardness shown comprises the specifica- 

 tion limits. A more detailed description of the properties of sheet 

 brass has been given elsewhere.- 



TABLE 1 



Chemical Composition of Non-Ferrous Sheet Spring Materials 



Brass 



Min., Max., 



per cent per cent 



Copper 64.5 67.5 



Lead 0.0 0.3 



Iron 0.0 0.05 



Zinc Remainder 



Nickel Silver 



Copper 53.50 56.50 



Nickel 16.50 19.50 



Zinc 25.50 28.50 



Iron 0.35 



Phosphor Bronze 



Copper 91.0 



Tin 7.50 8.50 



Phosphorus 0.05 0.25 



Iron 0.10 



Lead 0.02 



Antimony 0.01 



Zinc 0.20 



TABLE 2 

 Mechanical Properties of Non-Ferrous Sheet Spring Materials 



Brass 



2 "Physical Properties and Methods of Tests for Sheet Brass," by H. N. \'an 

 Deusen, L. I. Shaw, and C. H. Davis. Proceedings A.S.T.M., 1927. 



