CHAPTER VI 

 NICKEL SILVERS 



The copper-nickel-zinc alloys, like the copper-zinc 

 alloys, are of two general types: one containing 65 per 

 cent or more of copper and nickel combined and struc- 

 turally consisting of a single phase; the other containing 

 55 to 60 per cent of copper and nickel combined and 

 structurally consisting of two phases. Nickel is added 

 to copper zinc primarily for its influence on color. 

 Figure 1 shows the range of colors that may be secured 

 with nickel additions to copper-zinc alloys. 



The single-phase nickel silvers possess excellent cold- 

 working properties and only fair hot-working properties. 

 Accordingly they are most frequently used for those 

 applications requiring ductility in the cold condition. 



Figure 2 indicates the range of commercial nickel 

 silvers and their general working characteristics. 



Common name 



30 % nickel silver 



20 % niolcel silver 



20% nickel silver. . ., 



18% nickel silver 



18% nickel silver 



15% nickel silver 



12% nickel silver 



10% nickel silver 



10% nickel sUver 



6 % nickel silver 



18% nickel silver (spring stock) 

 12% nickel silver (leaded) 



Zinc, 

 • % 



5 



14 



16 



20 



19 



22 



23 



28 



33 



27 

 2% lead; 

 20%, zinc 



15 20 25 



Percen-i Nickel 

 Fig. 1. — Color trends of copper-; 



okel-zinc alloys, according to Kihlgren.*' 



The single-phase nickel silvers are used almost exclu- 

 sively for articles that are subsequently to be plated 

 such as tableware and hollow ware. However, the alloy 

 containing 55 per cent of copper and either 15 or 18 per 

 cent of nickel is used extensively as spring material, 

 because it possesses higher tensile properties in combina- 

 tion with higher modulus of elasticity than any of the 

 copper-zinc or copper-nickel-zinc alloys. 



Lead is frequently added to these nickel silvers to 

 improve machining, blanking, and shearing operations. 



The nominal composition of the more important of the 

 nickel silvers is given in the table on this page. 



The more important physical properties and a sum- 

 marization of mechanical properties of these alloys may 

 be found in Tables 1 to 13 on pages 191 to 222. Charts 

 1 to 108 on pages 192 to 225 give in detail the influence of 



cold working and the effect of various annealing treat- 

 ments on the mechanical properties. 



The alpha-beta nickel silvers can be readily hot-worked 

 by any of the commercial processes. Because of their 

 hot plasticity over a wide temperature range they can 

 be fabricated into difficult and intricate shapes, such as 

 plumbing fixtures, stair rails, architectural shapes, and 

 escalator parts. 



Occasionally lead is added to these alloys to improve 

 machining. The addition of lead does not interfere 

 with the hot-extrusion properties of these alloys but it 

 does make them unsuitable for hot-rolling and forging 

 operations. The mechanical properties of the more 

 important of these alloys have been developed by Cook^^*' 

 and are contained in Table 12 on page 221. 



