Building Design and Construction Handbook - Merritt - Ventech!

BUILDING MATERIALS 4.81
For flashing, copper is frequently coated with lead to avoid the green patina
formed on copper that is sometimes objectionable when it is washed down over
adjacent surfaces, such as ornamental stone. The patina is formed particularly in
industrial atmospheres. In rural atmospheres, where industrial gases are absent, the
copper normally turns to a deep brown color.
Principal types of copper and typical uses are:
Electrolytic tough pitch (99.90% copper) is used for electrical conductors—
bus bars, commutators, etc.; building products—roofing, gutters, etc.; process
equipment—kettles, vats, distillery equipment; forgings. General properties are high
electrical conductivity, high thermal conductivity, and excellent working ability.
Deoxidized (99.90% copper and 0.025% phosphorus) is used, in tube form, for
water and refrigeration service, oil burners, etc.; in sheet and plate form, for welded
construction. General properties include higher forming and bending qualities than
electrolytic copper. They are preferred for coppersmithing and welding (because of
resistance to embrittlement at high temperatures).
4.59 BRASS
A considerable range of brasses is obtainable for a large variety of end uses. The
high ductility and malleability of the copper-zinc alloys, or brasses, make them
suitable for operations like deep drawing, bending, and swaging. They have a wide
range of colors. They are generally less expensive than the high-copper alloys.
Grain size of the metal has a marked effect upon its mechanical properties. For
deep drawing and other heavy working operations, a large grain size is required,
but for highly finished polished surfaces, the grain size must be small.
Like copper, brass is hardened by cold working. Hardnesses are sometimes expressed
as quarter hard, half hard, hard, extra hard, spring, and extra spring, corresponding
to reductions in cross section during cold working ranging from approximately
11 to 69%. Hardness is strongly influenced by alloy composition,
original grain size, and form (strip, rod, tube, wire).
4.59.1 Plain Brass
Brass compositions range from higher copper content to zinc contents as high as
40% or more. Brasses with less than 36% zinc are plain alpha solid solutions; but
Muntz metal, with 40% zinc, contains both alpha and beta phases.
The principal plain brasses of interest in building, and their properties are:
Commercial bronze, 90% (90.0% copper, 10.0% zinc). Typical uses are forgings,
screws, weatherstripping, and stamped hardware. General properties include
excellent cold working and high ductility.
Red brass, 85% (85.0% copper, 15.0% zinc). Typical uses are dials, hardware,
etched parts, automobile radiators, and tube and pipe for plumbing. General properties
are higher strength and ductility than copper, and excellent corrosion resistance.
Cartridge brass, 70% (70.0% copper, 30.0% zinc). Typical uses are deep drawing,
stamping, spinning, etching, rolling—for practically all fabricating processes—
cartridge cases, pins, rivets, eyelets, heating units, lamp bodies and reflectors, elec-