Brass and Bronze
Brass and Bronze Alloy
Applications
Art Sculpture and Industrial Castings
All Brass and Bronze Products
Description
Copper is mankind’s oldest metal, dating back some 10,000 years. All of the great civilizations of the past, used copper and copper alloys (principally bronze and later brass) for both decorative and utilitarian purposes. Copper was used for military purposes, artistic applications such as church bells and statuary, tools and numerous other functional objects.
Copper alloys' unique combinations of mechanical and physical properties and excellent corrosion and wear resistance attributes have contributed toward copper and its alloys being the material of choice for building construction (e.g. plumbing, wiring and roofing), but have also led to the use of copper in many demanding engineering applications in the marine, automotive, chemical and electronics industries. Continuing developments in superconductors, electric vehicles, solar heating and large-scale desalination of water should ensure that copper remains an essential material in the future.
Today, copper and copper alloys remain one of the major groups of commercial metals, ranking third behind only iron/steel and aluminum in production and consumption. They are widely used because of their excellent electrical and thermal conductivities, outstanding resistance to corrosion, ease of fabrication and good strength and fatigue resistance. They are generally nonmagnetic. They can be readily soldered and brazed, and many coppers and copper alloys can be welded by various gas, arc and resistance methods.
For decorative parts, standard alloys having specific colors are readily available. Copper alloys can be polished and buffed to almost any desired texture and luster. They can be plated, coated with organic substances or chemically colored to further extend the variety of available finishes.
The elements most commonly alloyed with copper are aluminum, nickel, silicon, tin and zinc. Other elements and metals are alloyed in small quantities to improve certain material characteristic, such as corrosion resistance or machinability. Copper and its alloys are divided into nine major groups. These major groups are:
- Coppers, which contain a minimum of 99.3% Cu
- High-copper alloys, which contain up to 5% alloying elements
- Copper-zinc alloys (brasses), which contain up to 40% Zn
- Copper-tin alloys (phosphor bronzes), which contain up to 10% SN and 0.2% P
- Copper-aluminum alloys (aluminum bronzes), which contain up to 10% Al
- Copper-silicon alloys (silicon bronzes), which contain up to 3% Si
- Copper-nickel alloys, which contain up to 30% Ni
- Copper-zinc-nickel alloys (nickel silvers), which contain up to 27% Zn and 18% Ni
- Special alloys, which contain alloying elements to enhance a specific property or characteristic, for example, machinability.
Copper casting alloys are primarily selected for either their corrosion resistance or their combination of corrosion resistance and mechanical properties. These materials also feature good castability, high machinability and, compared with other corrosion-resistant alloys, reasonable cost. Additional benefits include biofouling resistance – important in marine applications – and a spectrum of attractive colors. Many of the alloys also have favorable tribological properties, which explains their widespread use for sleeve bearings, wear plates, gears and wear-prone components.
The copper-base casting alloys are designated in the Unified Numbering System (UNS) with numbers ranging from C80000 to C99999.
Brasses (C83300-C87900 and C89320-C89940) are copper alloys in which zinc is the dominant alloying addition, because of their excellent castability, relatively low cost and favorable combination of strength and corrosion resistance, brasses are by far the most commonly cast copper alloys. There are six subcategories of cast brasses; red and leaded red, semi red and leaded semi red, yellow and leaded yellow, high strength and leaded high-strength yellow (manganese bronzes), silicon brasses/silicon bronzes, and copper-bismuth (Cu-Bi) and copper-selenium-bismuth (Cu-Se-Bi) brasses.
Red brasses: The cast red brasses (C83300-C83810) are alloys of copper, zinc, tin and, in some cases, lead. A “red” copper like color is evident in alloys containing less than about 8% Zn.
Yellow brasses (C85200-C85800) span a broad range of zinc contents (20-40%). Yellow brasses have a pleasing light color and can be polished to a high luster.
High-strength Manganese brasses. also called manganese bronzes and high-tensile brasses,(C86100-C86800) are among the strongest (as-cast) copper-base materials. The high-strength yellow brasses are mainly used for gears, bolts, valve stems, bridge trunnions and other mechanical products requiring high-strength, good wear resistance and reasonably good corrosion resistance.
Silicon brasses/bronzes (C87300-C87900) include favorably low melting points and high fluidity. They are amenable to most casting methods, including permanent mold and pressure die casting processes.
Tin brasses. Tin is a potent solid-solution strengthener in copper. It also increases corrosion resistance, as the hundreds of surviving Bronze Age relics dramatically illustrate. Tin bronzes are stronger and more ductile than red and semi red brasses and are useable at higher temperatures than leaded alloys. Their high wear resistance and low friction coefficient against steel are useful in bearings, gears and piston rings.
Aluminum bronzes (C95200-C95900) are best known for their combination of exceptional corrosion resistance; high mechanical strength, toughness and wear resistance.
