Brass Knowledge

What is brass :
Brass is any alloy of copper and zinc; the proportions of zinc and copper can be varied to create a range of brasses with varying properties.

In comparison, bronze is principally an alloy of copper and tin.

Despite this distinction, some types of brasses are called bronzes. Brass is a substitutional alloy. It is used for decoration for its bright gold-like appearance; for applications where low friction is required such as locks, gears, bearings, ammunition, and valves; for plumbing and electrical applications..

Brass has a muted yellow color, somewhat similar to gold.

Brass has likely been known to humans since prehistoric times, even before zinc itself was discovered. It was produced by melting copper together with calamine, a zinc ore. In the German village of Breinigerberg, an ancient Roman settlement was discovered where a calamine ore mine existed. During the melting process, the zinc is extracted from the calamine and mixes with the copper. Pure zinc, on the other hand, has too low a boiling point to have been produced by ancient metalworking techniques. The many references to 'brass' appearing throughout the King James Bible are thought to signify another bronze alloy, or copper, rather than the strict modern definition of 'brass'

Important Properties of Brass :
Excellent Machinability

  • Sets the standard by which other materials are judged
  • Slight reduction in ductility when lead is present

Brass has excellent machinability and is the material by which all other materials are judged, however this can be improved even further by the addition of 3% lead to give free cutting high speed machining brasses. The addition of lead however gives a slight reduction in ductility.

Brass Families
There are three main families of wrought alloy brasses :

  • Copper-Zinc alloys
  • Copper-Zinc-Lead alloys (Leaded brasses)
  • Copper-Zinc-Tin alloys (Tin brasses)

Cast brass alloys can be broken into four main families :

  • Copper-Tin-Zinc alloys (red, semi-red and yellow brasses)
  • Manganese Bronze alloys (high strength yellow brasses) and Leaded Manganese Bronze alloys (leaded high strength yellow brasses)
  • Copper-Zinc-Silicon alloys (Silicon brasses and bronzes)
  • Cast Copper-Bismuth and Copper-Bismuth-Selenium alloys.