Properties Of Brass

Understanding the properties of brass will help you to choose the right material for your next project.

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Metals Centre stocks one grade of brass, viz. CZ121. Should you require a different grade of brass please be sure to inform us and we will do our best to get it for you.

Brass is one of the most commonly used metals today. Brass is a deriveative of copper when zinc is the primary alloying ingredient, besides copper.

Brasses may also have a small amount of other alloying elements in order to give it different advantageous properties.

What are the main distinguishing characteristics of brass?

Brass has excellent electrical conductivity and a high tensile strength. It rewards one with a brilliant shine when polished and there are as many types of brass as there are applications for it.

Brasses are suitable for fabrication via hot forging methods.The free machining grades set the bar for free machining, against which other metals are compared.

There are two classes of brass alloys viz.

  1. The alpha alloys - These are the brasses with less than 37% zinc.
  2. The alpha/beta alloys These have between 37 - 45% zinc.

The alpha alloys are ductile and therefore excellent for cold working. The alpha/beta or duplex alloys are limited in their cold ductility but are stronger and harder.

The properties of brass CZ121 are laid out below.

Please do not use this information for design purposes. This data is supplied only to assist you in comparing the different grades of metals that are available

Brass CZ121 Properties
Minimum Properties Ultimate Tensile Strength, (MPa)410
Proof Stress, 0.2% (MPa)
Elongation A5(%) 20
Hardness VPN
Chemistry Copper (Cu) 58%
Iron (Fe) -
Manganese (Mn) -
Nickel (Ni) -
Lead (Pb) 3% max
Zinc (Zn) Balance
Physical Properties Density8.47g cm3
Melting Point 875 deg
Modulus of Elasticity97 gpa
Electrical Resistivity0.062x10-6 ?.m
Thermal Conductivity123 W/m.K at 100°C
Thermal Expansion20.9 x10-6 /K at 100°C
Brass alloy CZ121corresponds to the following designations:

This is a good machining grade as it falls into the CZ121 class. The added element of lead improves its machinability. The lead does not dissolve in the brass and the tiny particles act as chip breakers. Sometimes the letter "M" is added to the designation CZ121"M", this referrs to its good machining qualities.

  • Corrosion resistance is fair to excellent

  • Cold working is not recommended. This alloy can be knurled if need be.

  • Hot working of CZ121 is excellent. This is best done between the temperature of 630 deg and 730 deg.

  • Annealing or solution treatment can be carried out by quick cooling after heating to between 430 deg and 600 deg Celsius.

  • Machinability is excellent. Its machinability rating is 90. As a comparison the Alloy 360 FC Brass is 100

  • Welding - Brazing is rated as good and soldering as excellent. Welding is fair, however all other welding methods are not recommended.

  • Supplied in the following formats: Round Bar, Hexagon Bar, Flat Bar and Square Bar.

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Unit C1, John st Warehouse
Selby ext. 11
South Africa

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