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The blending of various metals and elements to form alloys with
unique physical and mechanical properties has been a basic goal
of metallurgists for centuries. Thousands of years ago, ancient
metalworkers discovered how to alter the casing characteristics
of pure copper by adding various amounts of lead and tin, to produce
bronze alloys. The Egyptians, for example, were able to cast bronze
articles with incredibly thin sections, and they are commonly
credited with inventing the lost wax casting method.
Today over 140 copper-base alloys are recognized as commonly used
materials for casting. These alloys can be divided and subdivided
into the following categories:
… Coppers
… High Copper Alloys
… Brasses:
 - Copper-tin-zinc alloys (Red, semi-red and yellow brasses)
- High-strength yellow brasses (Manganese bronzes)
- Copper-silicon alloys (Silicon bronzes and silicon brasses)
… Bronzes:
- Copper-tin alloys (Tin bronzes)- Copper-tin-nickel alloys
(Nickel-tin bronzes)
- Copper-aluminum-iron and copper-aluminum-iron-nickel alloys
(Aluminum bronzes)
- Copper-nickel-iron alloys (Cupro nickels)
- Copper-nickel-zinc alloys (Nickel silvers
… Copper-Lead Alloys
… Special Alloys
NOTE: There are also lead-containing alloys for many of the categories
shown above, and they are commonly referenced to as leaded
red brasses, leaded manganese bronzes, leaded tin bronzes,
and so forth.
A series of lead-free alloys has recently been developed in response
to public concerns about the continued use of lead-containing
alloys in plumbing products and other applications. The new alloys
may contain up to 2% bismuth as a substitute for lead. Many of
the properties and casting characteristics, including the machinability
rating, are similar to the leaded alloys that they replace.
In North America, the Unified Numbering System has been adopted
to identify metals in an orderly manner and to avoid confusion
with names. For wrought and cast copper-base alloys, the designation
is the letter C followed by a five-digit number. It is an expansion
of the three-digit number used previously, and for example, Industry
Alloy No. 836 is now recognized as C83600.
The following table shows the nominal compositions for the most commonly used copper-base
casting alloys. It does not include all of the alloys available,
and additional information on them can be obtained from foundries,
ingot manufacturers, and the CCBDA.
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