Composition of Common Brass Alloys
Alloys Can Change the Properties of Brass
Brass is a metal alloy. It's always made with a combination of copper and zinc. By varying the amount of copper and zinc, it is possible to make harder and softer types of brass. Other metals, such as aluminum, lead, and arsenic may be used as alloying agents to improve machine ability and corrosion resistance.
How Different Alloys Change the Properties of Brass
By adding different metals to brass, it is possible to change its properties.
It can become yellower, harder, softer, stronger, or more corrosion-resistant, depending upon its chemical composition. For example:
- Brass is usually a warm golden color. The addition of 1% manganese, however, will turn brass to a warm chocolate brown color, while nickel will make it silver.
- Lead is often added to brass to make it softer and thus more malleable.
- Arsenic may be added to make brass more stable in certain environments.
- Tin can help to make brass stronger and harder.
Types of Brass
There are many different types of brass, each with a slightly different chemical composition. Each type of brass has its own name, qualities, and uses. For example:
- Red brass, not surprisingly, is warmer in color than other brasses. It is also a particularly strong type of brass.
- Cartridge brass (also referred to as 260 brass and yellow brass) is best known as an ideal metal for shell casings. It is most often sold in sheet form and is easily formed and worked into desired shapes.
- 330 brass is particularly useful in tubing and poles because it is both workable and machinable. It is commonly used for products such as fire poles.
- Free machining brass, also called 360 brass, is relatively high in lead. This makes it easy to cut and shape. It is often used to make items such as brass rods and bars.
- Naval brass, also called 464 brass, is highly corrosion resistant and thus ideal for use in seawater.
Compositions of Common Brass Alloys
The chart below summarizes the composition of a number of commonly used brass alloys:
|C21000||210||95/5 Gilding metal||-||CuZn5||C2100||94-96||~5||-|
|C22000||220||90/10 Gilding metal||CZ101||CuZn10||C2200||89-91||~10||-|
|C23000||230||85/15 Gilding metal||Cz103||CuZn20||C2300||84-86||~15||-|
|C24000||240||80/20 Gilding metal||Cz103||CuZn20||C2400||78.5-81.5||~20||-|
|C26130||259||70/30 Arsenical brass||Cz126||CuZn30As||C4430||69-71||~30||Arsenic|
|C26800||268||Yellow brass (65/35)||Cz107||CuZn33||C2680||64-68.5||~33||-|
|C27000||270||65/35 Wire brass||Cz107||CuZn35||-||63-68.5||~35||-|
|C27200||272||63/37 Common brass||Cz108||CuZn37||C2720||62-65||~37||-|
|C38000||380||Section brass||Cz121||CuZn43Pb3||-||55-60||~43||1.5-3.0||Aluminum 0.1-0.6|
|C38500||385||Free cutting brass||Cz121||CuZn39Pb3||-||56-60||~39||2.5-4.5||-|