Copper, Brass and Bronze, otherwise known as the “Red Metals”, may look the same initially but are actually quite different.

Copper

Copper is used in a wide range of products due to its excellent electrical and thermal conductivity, good strength, good formability and resistance to corrosion. Pipe and pipe fittings are commonly manufactured from these metals due to their corrosion resistance. They can be readily soldered and brazed, and many can be welded by various gas, arc and resistance methods. They can be polished and buffed to almost any desired texture and luster.

There are grades of unalloyed Copper, and they can vary in the amount of impurities that are contained. Oxygen-free copper grades are used specifically in functions where high conductivity and ductility are needed.

One of the most important properties of copper is its ability to fight bacteria. After extensive antimicrobial testing by the Environmental Protection Agency, it was found that 355 copper alloys, including many brasses, were found to kill more than 99.9% of bacteria within two hours of contact. Normal tarnishing was found not to impair antimicrobial effectiveness.

Copper Applications

Copper was one of the earliest metals discovered.  The Greeks and Romans made it into tools or adornments, and there are even historical details showing the application of copper to sterilize wounds and purify drinking water. Today it is most commonly found in electrical materials such as wiring because of its ability to effectively conduct electricity.

Brass

Brass is mainly an alloy that consists of copper with zinc added. Brasses can have varying amounts of zinc or other elements added. These varying mixtures produce a wide range of properties and variation in color. Increased amounts of zinc provide the material with improved strength and ductility. Brass can range in color from red to yellow depending on the amount of zinc added to the alloy.

• If the zinc content of the brass ranges from 32% to 39%, it will have increased hot-working abilities but the cold-working will be limited.

• If the brass contains over 39% zinc (example – Muntz Metal), it will have a higher strength and lower ductility (at room temperature).

Brass Applications

Brass is commonly used for decorative purposes primarily because of its resemblance to gold. It is also a commonly used to make musical instruments due to its high workability and durability.

Other Brass Alloys

Tin Brass
This is an alloy that contains copper, zinc and tin. This alloy group would include admiralty brass, naval brass and free machining brass. The tin has been added to inhibit dezincification (the leaching of zinc from brass alloys) in many environments. This group has low sensitivity to dezincification, moderate strength, high atmospheric and aqueous corrosion resistance and excellent electrical conductivity. 

They possess good hot forgeability and good cold formability. These alloys are typically used to make fasteners, marine hardware, screw machine parts, pump shafts and corrosion-resistant mechanical products.

Bronze

Bronze is an alloy that consists primarily of copper with the addition of other ingredients. In most cases the ingredient added is typically tin, but arsenic, phosphorus, aluminum, manganese, and silicon can also be used to produce different properties in the material. All of these ingredients produce an alloy much harder than copper alone.

Bronze is characterised by its dull-gold colour. You can also tell the difference between bronze and brass because bronze will have faint rings on its surface.

Copper Nickel Grade

90-10 – 90/10 cupronickel is a 90% copper, 10% nickel alloy that also contains small but important additions of iron and manganese to enhance overall strength corrosion resistance. This, combined with high ductility and toughness, makes it a popular grade for marine, architectural and industrial applications. Offers excellent resistance to stress corrosion, erosion, and biofouling in seawater and brackish water, excellent fabrication and welding properties, a high resistance to hydrogen embrittlement and the retention of mechanical properties down to cryogenic temperatures.

70-30 – 70/30 is a 70% copper, 30% nickel alloy with additions of iron and manganese. These elemental additions make it somewhat more resistant to corrosion and erosion and with slightly improved strength level than 90/10, making it suitable for more demanding applications. In particular, its corrosion resistance is notably improved in high-velocity waters (up to 4.5m/s) and polluted seawater. 70/30 is readily cold worked, fabricated and welded without any special material considerations.