The Coppers 



Arsenical Copper. — Copper containing arsenic in 

 moderate amount appears to form a tenacious, adherent, 

 initial film on exposure to the atmosphere and many 

 other corrosive media. With such coppers subsequent 

 mild corrosion appears to progress uniformly and without 

 causing pitting. 



In mechanical applications where vibration and 

 alternation of stresses by reason of expansion and 

 contraction introduce the possibility of cracking or 

 failure in fatigue, the presence of small pits introduces 

 the notch effect with a drastic lowering of the resistance 

 of the copper to fatigue failure. Arsenical coppers 

 find useful application where stresses of this type are 

 to be combated. 



It has also been observed that copper containing 

 arsenic in moderate amount hardens less rapidly on cold 

 working than arsenic-free copper. This in itself indicates 

 a higher resistance to failure in corrosion fatigue, particu- 

 larly as influenced by the notch effect. 



The arsenical coppers are widely used in England and 

 have found wide application in the construction of such 

 parts as locomotive fireboxes where the arsenic appears to 

 prevent excessive scaling of the metal at elevated 

 temperatures. In this country the use of deoxidized 



arsenical copper as a condenser tube material for com- 

 bating the corrosive attack of inland waters is growing. 

 More recently tough-pitch arsenical copper with an 

 arsenic content of 0.3 to 0.5 per cent arsenic has found 

 wide application in the building field as roofing, flashing, 

 and gutter material. 



Tellurium Copper. — This alloy is rapidly supplanting 

 leaded copper in the fabrication of electrical hardware 

 requiring machining operations in its manufacture. 



Fire -refined Copper. — This type of copper, resulting 

 either from the processing of scrap metal or from the 

 treatment of ores, is usually cast as ingot bar for use in 

 the production of copper-base alloys. 



However, shapes cast for use in the direct fabrication 

 of wrought-copper forms are produced in certain types 

 of fire-refined coppers. In general, such copper is used 

 in applications which do not require the higher electrical 

 conductivities attainable with electrolytically refined 

 copper. 



Tables 1 to 8 on pages 4 to 23 give the physical proper- 

 ties and a summarization of the mechanical properties of 

 the more important coppers. Charts 1 to 74 on pages 

 3 to 26 show in greater detail the effect of cold working 

 and annealing on the mechanical properties. 



to 



70 



65 



60 



55 



50 



45 



c-40 



Qj 35 

 Q. 



jQ 30 



_j 



§ 25 



o 



~"20 



15 



10 



5 







O.IO 0.20 0.30 040 0.50 0.60 0.70 030 0.90 -1.00 

 Percent Phosphorus 

 Chart 1. — The effect of phosphorus on the electrical conductivity, 

 thermal conductivity, and tensile strength of copper, cold-rolled 

 6 B. & S. Nos. (50 per cent reduction of area). Based on data by 

 Smith.'88> 



750 



,600 



E 450 



c 300 



150 







10 



15 20 25 30 35 40 45 50 

 Silver-Oz per Ton 



Chart 2. — The effect of silver on the softening temperature of cold- 

 worked tough-pitch copper according to J. L. Gregg.*^ 



