Copper, brass, and bronze alloys are non-ferrous metals with excellent electrical and thermal conductivity as well as good corrosion resistance, ductility, and strength.

Copper is a reddish orange, soft, and malleable (low hardness) metal that is a good conductor of heat and electricity. Pure copper is mainly used for heat and electrical transfer applications, as most alloy additions detrimentally affect copper’s conductivity properties. Common applications include electronics, plumbing, and heat exchangers.

Brass is an alloy of copper and zinc; the proportions of zinc and copper can be varied to create a range of brasses with varying properties. Brasses set the standard by which the machinability of other materials is judged and do not become brittle at low temperatures like mild steel. Brass has excellent thermal conductivity and is a first choice for heat exchangers. Disinfection is a unique property of brass, as common pathogens die on its surface within hours, making it ideal for doorknobs and other devices commonly touched by human hands.

Bronze is an alloy of copper and usually tin as the main additive that is much harder and more brittle than brass. The term “bronze” is sometimes used interchangeably for different types of copper alloys, but the most common typically refers to a mix of about 90% copper and 10% tin in its “pure” form. Common additives to bronze include phosphorous to harden bronze and lead to make bronze more castable. It creates little friction and does not spark, making it ideal for metal on metal contact applications such as gears and for tools used in combustible environments.

Specifications

Selecting metal alloys requires an analysis of the desired dimensions and specifications. Dimensions to consider include:

• Outer diameter (OD)
• Inner diameter (ID)
• Overall length
• Overall thickness

Other specifications of importance (based on application) include product shape, tensile strength, yield strength, melting point, conductivity, corrosion resistance, ductility, and malleability. These properties differ based on the forming method and alloy composition.

Image credit:

Freeport-McMoRan Copper & Gold, Inc. (FCX)