What is the difference between copper and brass?
Our customers may ask from time to time about the differences copper and brass, basically these two metal materials are similar, however people could tell them by color, chemical composition, mechanical strength, application, conductivity, corrosion resistance quality and cutting property.
Chemical composition
| Main % | Other % (max) | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cu (min) | P | Mn | Bi | Sb | As | Fe | Ni | Pb | Sn | S | Zn | O | Sub Total |
| 99.5 | 0.1~0.04 | n/a | 0.003 | 0.05 | 0.05 | 0.05 | 0.2 | 0.01 | 0.05 | 0.01 | n/a | 0.01 | 0.49 |
| Main % | Other % (max) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Cu | Sn | Fe | Al | Zn | Pb | Fe | Sb | Bi | P | Sub Total |
| 67.0~63.5 | n/a | n/a | n/a | 32.7~36.2 | 0.03 | 0.10 | 0.005 | 0.002 | 0.01 | 0.3 |
Appearance color
It is easy to tell cooper and brass by color. The origin color of copper is rose, but copper's surface has an oxidation film, which is purple. So most of time, copper's appearance color is burgundy, in Chinese, we also call it "purple copper". Brass has a light golden apprearance.
Conductivity
Copper has a great property for thermal & electricity conductivity, actually the only metal got better conductivity property is silver, which is much more expensive than copper.
For this reason, copper products are widely used for thermal & conductivity, such as core of electric wire, various kinds of radiator.
Brass conducitivity is not as good as copper, please see the table below.
| Metal | Conductivity Property | |
|---|---|---|
Thermal Conductivity w/(m.k) | Electrical Resistivity (20℃) Ω·mm2/m | |
| Copper | 386.4 | 0.018 |
| Brass | 108.9 | 0.071 |
Density
The density of copper is 8.9~8.95, and brass is 8.52~8.62, as we could see, copper has higher density than brass.
Mechanical Property
Copper has better elongation property and brass offers better tensile strength property. Pure copper of water drop size cold be elongated to thread of 2 km.
| Metal | Product Form | Temper | Tensile strength kg/mm³ (min) | Elongation % (min) |
|---|---|---|---|---|
| Copper | Sheet | Annealed | 20 | 30 |
| Hard | 30 | 3 | ||
| Pipe | Annealed | 21 | 35 | |
| Hard | 30 | n/a | ||
| Brass | Sheet | Annealed | 30 | 40 |
| Half hard | 35 | 25 | ||
| Hard | 40 | 15 | ||
| Pipe | Annealed | 30 | 38 | |
| Half hard | 35 | 30 |
Corrosion resistance
Copper has better corrosion resistance property than brass. Copper has good corrosion resistance in the atmosphere, seawater and certain non-oxidizing acids (hydrochloric acid, dilute sulfuric acid), alkali, salt solution and various organic acids (acetic acid, citric acid).
Cutting property
Cutting brass is easiler than cutting copper.
Price
Normally copper price is higher than brass price.
