Mac Metals > Products & Services > Benefits of Copper Alloys
Unified Numbering System
A Unified Numbering System has been developed for metals and alloys by ASTM and SAE. CDA administers the section on copper and its alloys. This system is based on wrought alloy numbers ranging from C10000 through C79999. Cast alloy numbers range between C80000 and C99999.
Major End-Use Applications Groupings
Since color is the dominant decision making factor (after basic performance characteristics), CDA has grouped architectural alloys of various forms (extrusions, sheet and plate, castings, etc) together for color matching purposes. A wide variety of copper alloys are available for use in architectural applications. The variations in color stem primarily from differences in chemical composition. Production and forming methods may affect alloy selection. Additional information is available upon request. The CDA publication Copper Brass Bronze – Architectural Applications covers the selection process in greater detail.
Technically, alloys primarily of copper and tin are considered bronzes, while those chiefly of copper and zinc are brasses. In practice, however, the term bronze is commonly used for a variety of copper alloys, including those with little or no tin. This is because they resemble true bronzes in both natural and weathered colors.
Nickel silvers are commonly identified as "white bronze" and contain no silver, but have varying amounts of nickel, creating a silver color.
Although the terminology can be confusing, Mac Metals offers a full range of alloys to meet the performance and color requirements for any architectural application.
Benefits of Brass, Bronze and Nickel Silver
Brass, bronze and nickel silver are copper alloys that benefit from a well developed recycling infrastructure and an economic value that drives recovery, recycling and reuse. "Green" initiatives, including LEEDS, require recyclability, recycled content, sustainability and energy efficiency—all features of the copper alloys that Mac Metals produces.
Resistance To Weathering
Architectural bronze, brass and nickel silver alloys are resistant to atmospheric corrosion and have an unlimited life span. It develops a durable oxide film (patina) and has a self-healing quality that hides, or blends over superficial scratches.
Maintenance of brass, bronze and nickel silver is unique because these metals can be restored to their original appearance even after years of neglect.
The basic price of brass, bronze and nickel silver may be higher than some alternatives, but that is only a small part of the overall cost calculation. Mac Metals extrusions eliminate much of the cost required to produce finished components. When the value of the scrap is included, the overall price may be less expensive than other lower cost materials. Consider wear characteristics, corrosion resistance, tooling costs and close tolerance capabilities to appreciate the overall cost effectiveness of brass extrusions.
Unique Color, Texture
No other metals family creates the exciting visual possibilities and aesthetic beauty offered by the copper alloys produced by Mac Metals.
Surface Treatments, Accepts Mirror-Like Finish
All of Mac Metals production and specialty alloys can be successfully polished to either a high gloss or mirror finish. To maintain a polished finish, the use of protective lacquers and coatings is recommended.
Excellent Machining Characteristics
While all brasses are easy to machine, the addition of small amounts of lead to brasses improves this property. C36000 is universally accepted as the standard for machinability. All of Mac Metals copper alloys have excellent machining characteristics. This affords higher machining speeds and lower rates of tool wear while maintaining tolerances and surface finish.
Good Strength and Ductility
Extruded shapes are wrought under pressure. And have a tensile strength in excess of 45,000 lbs. per square inch.
Spark Resistance
Brasses do not spark when struck and are approved for use in hazardous environments.
Temperature Tolerant
Brass, bronze and nickel silver will not soften in high temperatures, or embrittle in low temperatures.
Atmospheric exposures of the brasses result in the development of a superficial film. Outdoor exposure will ultimately result in the formation of a thin protective 'patina' which is frequently seen as a visually attractive feature in buildings, but the brass will remain essentially unaffected for an unlimited amount of time.
Magnetic Permeability
Because brasses are non-magnetic, they are commonly specified in electrical equipment and instrumentation applications.
Brass can be easily joined to itself and all other copper alloys, by soft soldering and brazing. Fabrication of intricate brass work is much easier than some other metals and results in cleaner lines due to the elimination of screws, rivets and other connecting devices.
Decorative and Protective Finishes
Modern decorative techniques are available for toning brass to almost any desired color from gold-like yellow, to amber browns to chocolate browns and blacks. All these colors have a long life even in working environments.
Brass can be polished to a high gloss, or mirror finish. Left untreated brass will tarnish, but there are a number of protective lacquers and coatings that protect the desired finish.
Anti-Microbial Properties
The Environmental Protection Agency has registered copper, brass and bronze as antimicrobial and is allowing public health claims to be made about their effectiveness against Staphylococcus aureus, MRSA, E. coli O157:H7, Enterobacter aerogenes and Pseudomonas aeruginosa. Copper alloys are a supplement to existing infection control practices and are not a replacement for good hygiene and surface disinfection. Copper alloy surfaces have been shown to reduce microbial contamination, but they do not necessarily prevent cross-contamination. Mac Metals continues to investigate opportunities to register potential copper alloys and participate in the manufacture of extrusion for anti-microbial applications.