Copper Alloys
About Our Copper Alloys
Waukesha Foundry produces a range of copper-based alloys designed for applications requiring corrosion resistance, wear performance, and reliable mechanical properties. Our capabilities include aluminum bronze, manganese bronze, silicon brass, silicon bronze, tin bronze, and other corrosion-resistant copper alloys.
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Copper and its alloys are among the most versatile engineering materials available. Pure copper is recognized for its exceptional thermal and electrical conductivity, but it is the wide range of various copper alloys formed by introducing different elements such as zinc, tin, chromium, manganese, aluminum, and others that makes copper-based materials an ideal choice across so many demanding industries. These alloys offer excellent corrosion resistance, strong bearing surface qualities, favorable tensile strength, and solid machinability, making them well suited for marine environments, processing equipment, and components exposed to harsh operating conditions.
One notable property shared by popular copper alloys is that they are fully recyclable without losing their core properties. This is a significant advantage in manufacturing environments focused on sustainability and material efficiency.
In addition to traditional copper alloys, Waukesha Foundry also offers WM126, a copper-based alloy commonly used in anti-galling applications. While it is featured within our anti-galling materials, its copper composition makes it a strong option for applications requiring enhanced wear resistance alongside corrosion performance.
Understanding Copper Alloys
At their core, copper alloys begin with pure copper: a reddish-colored metal with a melting point of approximately 1,085°C, lower than most structural alloys. Pure copper is prized for its thermal conductivity and electrical conductivity, but alloying it with other metals allows engineers to tailor hardness, tensile strength, yield strength, corrosion resistance, and machinability for specific applications.
There are over 400 different copper alloy compositions in use across industries today. These fall into several broad families:
Brasses (Copper-Zinc Alloys)
Brass alloys combine copper with zinc, typically in varying proportions, producing materials known for their yellow-gold color and high ductility. These copper-zinc alloys offer fair electrical characteristics and are widely used in connectors, fittings, and architectural components.
Bronzes (Copper-Tin Alloys)
Bronze alloys typically contain copper with tin as the primary alloying element. Traditional bronze alloys contain roughly 12–12.5% tin along with copper, delivering high strength, good hardness, and excellent corrosion resistance. Silicon bronze substitutes silicon for tin, while aluminum bronze uses aluminum. Both are popular copper alloys for demanding structural and marine applications.
Cupronickel (Copper-Nickel Alloys)
Cupronickel is a copper-nickel alloy renowned for outstanding seawater corrosion resistance and low reactivity with marine environments. It maintains structural integrity under high temperatures and is widely used in heat exchangers, desalination equipment, and marine hardware.
Nickel Silver
Despite its name, nickel silver contains no actual silver. It is a copper-nickel-zinc alloy with a silvery-white appearance, offering good hardness, corrosion resistance, and a bright finish. It is commonly used in decorative applications, connectors, and precision components.
Key Benefits of Copper Alloys
- Exceptional corrosion resistance, including marine, chemical, and food-processing environments
- Strong wear resistance and bearing surface performance
- High thermal conductivity, supporting heat dissipation in exchangers and temperature-critical components
- Good electrical conductivity across many alloy families
- Tensile strengths ranging from 32,000 PSI to over 200,000 PSI depending on alloy and heat treatment
- Favorable ductility and malleability for complex casting geometries
- Excellent machinability across many alloy types
- Fully recyclable without loss of properties, a key advantage in sustainable manufacturing
- Low reactivity with many food products, making them ideal for food and dairy processing equipment
Common Copper Alloy Applications
The combination of properties that copper alloys offer (corrosion resistance, strength, machinability, and thermal performance) makes them a reliable choice across a broad range of industries and applications:
- Marine and seawater systems
- Desalination equipment
- Pumps, valves, and impellers
- Food, dairy, and beverage processing equipment
- Pharmaceutical processing pumps
- Heat exchangers and temperature-control systems
- Bearings, bushings, and gears
- Electrical and electronic connectors
- Industrial and processing equipment
Material Spotlight: Waukesha Metal 3 (WM3), Copper-Nickel Alloy
WM3 is Waukesha Foundry’s proprietary copper-based alloy, formulated for excellent strength, corrosion resistance, and anti-galling performance. It is often referred to as “dairy metal” because it does not impart off-tastes in dairy products and withstands the corrosive effects of lactic acid. WM3 does not require lubrication, making it well suited for clean environments where lubricant use is prohibited.
Thanks to its copper-based composition, WM3 offers higher thermal conductivity compared to many nickel-based alloys in the Waukesha Metals portfolio, making it a strong choice for components where heat dissipation and temperature control matter.
Key Properties of WM3
- Material Type: Copper-based alloy
- Excellent corrosion resistance in seawater and marine environments
- Outstanding anti-galling performance against stainless steel, Inconel®, Monel®, and chromium-plated surfaces
- High thermal conductivity for heat exchangers and temperature-critical components
- Resistant to stress corrosion cracking and crevice corrosion
- Readily machinable with or without coolant
- Food-grade: approved for direct food contact
Primary Applications of WM3
- Food processing equipment
- Dairy and beverage processing
- Pharmaceutical processing pumps
- Seawater and desalination equipment
- Gears, bushings, and bearings
- Quick-snap couplings, pistons, and transfer car nuts/bolts
Corrosion Resistance: WM3 performs reliably in seawater, acidic environments, and applications with aggressive cleaning or sterilization cycles. It resists stress corrosion cracking and crevice corrosion, making it a proven performer in marine and food-grade applications alike.
Considerations: WM3 may be susceptible to corrosion in environments containing high levels of sulfides or ammonia. Machinability is fair to good. Generally non-weldable.
The Waukesha Foundry Difference
Waukesha Foundry works closely with customers to select the right copper alloy based on performance requirements, environment, chemical composition needs, and application. With over a century of metallurgical expertise, our engineering team understands that conditions such as temperature variations, bearing load, mating materials, and operating speed are all factors in determining the right alloy for your application.
We conduct extensive testing on the corrosive effect of chemicals and food products on high-alloy materials, and our in-house capabilities (including nondestructive testing, precision machining, and solidification modeling) ensure each casting is engineered to meet the demands of its end use. We can produce castings ranging from 1 pound to over 6,000 pounds across more than 200 different alloys.
FAQs
What makes copper alloys different from pure copper?
Pure copper delivers exceptional electrical and thermal conductivity, but its mechanical properties (hardness, tensile strength, and yield strength) are relatively limited on their own. By introducing different elements such as zinc, tin, aluminum, chromium, manganese, or nickel, engineers can dramatically expand the performance envelope of copper and its alloys. The result is a large family of various alloys, each tuned for specific combinations of strength, corrosion resistance, machinability, and thermal or electrical conductivity.
What is the difference between brass alloys and bronze alloys?
Both are popular copper alloys, but they differ in their primary alloying elements. Brass alloys are copper-zinc alloys known for their yellow-gold color, high ductility, and fair electrical characteristics. Bronze alloys are primarily copper-tin alloys, traditionally containing around 12–12.5% tin, which delivers higher hardness and strength than brass and outstanding corrosion resistance, making bronzes the preferred choice for marine, bearing, and pump applications.
What is cupronickel and where is it used?
Cupronickel is a copper-nickel alloy with outstanding seawater corrosion resistance and low reactivity in marine environments. It maintains performance under high temperatures and is widely used in desalination equipment, heat exchangers, marine hardware, and any application requiring consistent performance in saltwater conditions.
What is nickel silver and does it contain actual silver?
No. Despite its name, nickel silver contains no silver whatsoever. It is a copper-nickel-zinc alloy that takes its name from its silvery-white appearance. Nickel silver offers good hardness, corrosion resistance, and an attractive finish, making it popular in connectors, precision components, and architectural applications.
What tensile strength can copper alloys achieve?
Copper alloys offer a wide range of mechanical properties depending on their chemical composition and heat treatment. Tensile strengths can range from approximately 32,000 PSI in softer, more malleable alloys to over 200,000 PSI in high-strength variants. For example, WM126 provides a minimum tensile strength of 50 ksi and a yield strength of 39 ksi with an average Brinell hardness of 150 BHN, making it well suited for gears, bushings, bearings, and other wear-intensive components.
Are copper alloys suitable for food processing and hygienic applications?
Yes. Several of the copper alloys Waukesha Foundry produces are approved for direct food contact. WM3, for instance, is a food-grade copper alloy that does not impart off-flavors in dairy products and resists the corrosive effects of lactic acid. WM126 is also widely used in meat processing plants for form plates, plungers, and vane pumps. Both alloys withstand frequent cleaning and sterilization cycles without requiring lubrication, a critical requirement in food and pharmaceutical environments.
How does thermal conductivity factor into copper alloy selection?
Thermal conductivity is an important selection criterion when efficient heat transfer is required. WM3, for example, offers higher thermal conductivity than many nickel-based alloys in the Waukesha Metals portfolio, making it a strong choice for heat exchangers and other components where temperature control is critical. Copper’s inherently high thermal conductivity is one of the reasons copper and its alloys are used in heat exchangers, desalination systems, and industrial cooling applications across many industries.
Can copper alloys be recycled?
Yes. One of the most valuable attributes of copper alloys is that they are fully recyclable without losing their core properties. This makes them an attractive choice in manufacturing environments focused on sustainability and material efficiency. In fact, Waukesha Foundry’s WM88 Buy Back Program reflects this value: because WM88 is a proprietary alloy, we can purchase back used rotors, plugs, drop-offs, and machine-segregated chips at highly competitive rates.
How do I know which copper alloy is right for my application?
Selecting the right alloy depends on a range of factors: the operating environment (seawater, chemical, food-grade), temperature range, mating materials, bearing load, and whether lubrication is permitted. Waukesha Foundry’s team of degreed metallurgical engineers works closely with customers to evaluate these parameters and recommend the most appropriate alloy. Our online Alloy Selector Tool is also a useful starting point. Contact us to speak with an expert.