90 



Copper and Copper-base Alloys 



Leaded high brass has the same copper content as com- 

 mon high brass, which is one of the most popular of all 

 the brasses and which is used extensively for deep draw- 

 ing, stamping, or any cold operation requiring unusual 

 ductility. Lead is present in this mixture to improve 

 piercing, punching, and shearing operations. Because 

 of the high copper and reasonably low lead content, this 

 alloy is well suited for those applications requiring good 

 machinability, shearing, and punching properties in 

 combination with reasonablj^ good bending and forming 

 properties. It is extensively used for the manufacture 

 of plumbing parts and is most commonly fabricated in 

 strip form. Its physical properties and general mechan- 

 ical properties are given in Table 3. More detailed 

 data are given in Charts 21 to 32 on pages 98 to 100. 



Leaded-brass rod, because of its copper and low lead 

 content, has the same desirable properties as leaded high 

 brass and it is suited for applications requiring these 

 properties. This alloy is seldom supplied except in 

 rod form. It is used in the manufacture of spark-plug 

 terminals, battery terminals, and similar machined parts 

 that are required to be knurled. Its physical and general 

 mechanical properties are showTi in Table 4 on page 101. 

 More detailed mechanical data are given in Charts 33 to 

 40 on pages 101 to 103. 



Heavy-leaded brass containing 2.50 per cent of lead 

 and engraver's brass containing 1.50 per cent of lead are 

 used extensively for applications involving good free- 

 cutting properties. The more severe the engraving 

 and/or tooling, the higher the lead content mil be. 

 Both of these alloys have poor bending or forming proper- 

 ties and are usually fabricated in strip form only. Their 

 phj^sical and general mechanical properties are given in 

 Tables 5 and 6 on pages 103 and 107. Greater detailed 

 mechanical properties are shown in Charts 41 to 63 on 

 pages 104 to 110. 



Free-cutting brass rod is the most important of all the 

 leaded brasses. Each year millions of pounds are con- 

 sumed in the manufacture of screws, nuts, bolts, door 

 hinges, and general hardware of all kinds. This product 

 has excellent plasticity within a temperature range of 

 1200 to 1450° F. and can be extruded into intricate 

 shapes. It cannot be hot-rolled or forged because of its 

 high lead content. It is usually fabricated bj^ hot ex- 

 truding and cold drawing to size. Commercially free- 

 cutting brass rod is furnished in the hard condition for 

 best machining properties. If very light upsetting opera- 

 tions are necessary in the manufacture of a specific part, 

 it is best practice to use an annealed or soft rod, thereby 

 sacrificing somewhat machining or free-cutting properties 

 in order to obtain the ductility required. Physical and 

 general mechanical properties are shown in Table 9 on 

 page 115. More detailed data are given in Charts 80 to 

 87 on pages 116 and 117. 



Deep-drilling rod, as the name implies, is used for 

 parts requiring deep and accurate drilling. Because of 

 the very high lead content of this alloy, tool and drill 

 wear is reduced to a minimum. This allov is most com- 



monly supplied in the form of rod. Physical and general 

 mechanical properties are given in Table 11 on page 120. 

 Charts 94 to 100 on pages 120 to 122 give in greater 

 detail the effect of cold working and annealing on the 

 mechanical properties. 



Riveting and turning rod represents a compromise 

 between good machining and forming properties. This 

 alloy has good free-cutting properties and in addition 

 can be lightly cold-worked by such operations as riveting, 

 flanging, upsetting, knurling, and roll threading. Its 

 physical and general mechanical properties are given in 

 Table 7, and Charts 64 to 69 on pages 111 aild 112 show 

 the effect of cold drawing and annealing on the mechan- 

 ical properties. 



Low-leaded rod is used extensively in the manufacture 

 of screws, bolts, and like parts, which require for their 

 manufacture good cold-upsetting properties in combina- 

 tion with fair machinability. Although this alloy is 

 considerably more difficult to machine than free-cutting 

 brass, the presence of 0.50 per cent of lead drastically 

 increases the machinability over that of a non-leaded 

 brass in this composition range at not too great a sacri- 

 fice of ductility. For example, an addition of 0.60 per 

 cent of lead to an alloy of this type reduces the power 

 required by machining 46 per cent; a 3.5 per cent lead 

 addition will reduce it by only 15 per cent more. Physi- 

 cal and general mechanical properties are given in 

 Table 10. Charts 88 to 93 on pages 1 18 and 1 19 show the 

 influence of cold working and annealing treatment. 



Forging rod is used almost exclusively for the produc- 

 tion of hot pressings and hammer forgings. It contains 

 the maximum of lead that will not cause difficulty in its 

 copper range in hot forging. This alloy is extremely 

 plastic within a temperature range of 1200 to 1450°F. and 

 can be shaped hot into a multiplicity of shapes. It is 

 used for the fabrication of all kinds of brass hardware, 

 ammunition parts, transformer caps, valve stems, plumb- 

 ing fixtures, and similar parts. Lead is present as an 

 aid to machinability and also to improve piercing, punch- 

 ing, and shearing operations. The physical and general 

 mechanical properties of brass forging rod are given in 

 Table 12. For greater detail see Charts 101 to 107 on 

 pages 123 and 124. 



Architectural bronze and extruded-shape brass, be- 

 cause of their lower copper content and consequentlj^ 

 greater amount of beta phase, are considerably more 

 plastic than forging rod and consequently can be extruded 

 with less power and greater ease into more intricate 

 shapes. These leaded alloys may contain a small 

 amount of aluminum added primarily for its effect on 

 color. Copper-zinc alloys in this range of copper have a 

 color approximating the "bronzes" and for this reason 

 are known commercially as "architectural bronze." As 

 the name implies, they are used for architectural trim in 

 such applications as door frames, jambs, thresholds, cor- 

 nices, and window sash. Physical and general mechanical 

 properties are shown in Tables 13 and 14 on pages 125 

 and 127. Charts 108 to 120 on pages 125 to 129 give in 



