452 APPLIED SCIENCE 



628. Brass. Brass is an alloy of copper and zinc. The 

 malleability and ductility of this alloy depend upon the 

 amount of copper in the mixture. The ordinary yellow 

 brass of commerce, known as high brass because it contains 

 a large amount of zinc, varies from 60% copper and 40% 

 zinc to 75% copper and 25% zinc. Brass is used in the 

 joining of pipes because it does not rust or corrode as iron 

 does. 



629. Anneals and Tempers of Sheet Metals. Sheet 

 metals are used to meet definite conditions and are softened 

 or hardened accordingly. The degree of softness is expressed 

 as "anneal " and the degree of hardness as temper. There- 

 fore in describing a sheet metal, the character of the " an- 

 neal " or the temper should be specified. To illustrate, the 

 temper of sheet brass may be expressed as "half-hard," 

 "hard," or "spring." 



530. Extended Metal Shapes. There are many brass and 

 bronze alloys that may be made into irregular shaped bars 

 by forcing the hot metal through dies of the required shape. 

 These bars are spoken of as extended metal. 



531. German Silver. German silver is an alloy of nickel, 

 copper, and zinc. Its quality is designated by figures which 

 indicate the percentage of nickel in the mixture. It is called 

 white metal when containing 18% or more of nickel. As the 

 percentage of nickel is reduced, its color shades off towards 

 the yellow color of brass. While German silver is not so 

 soft and ductile as brass, it may be worked and spun to 

 shapes on chucks of lathes. The metal has a very fine, 

 dense grain, takes a high polish, is non-corrosive under atmos- 



