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Chemical Formula |
| Cu/Zn Alloys |
Topics Covered |
| Background Key Properties Applications High Pressure Gas Valves Plumbing Systems Marine Applications Gilding Metals Other Applications |
Background |
| Brasses are alloys of copper and zinc (generally 5 to 40%), and may contain small amounts of other alloying elements. Most are available in a range of forms and can be fabricated by casting, forging, stamping, rolling, extrusion and machining. They fall into two classes, the alpha alloys with less than 37% zinc which are ductile and can be cold worked and the alpha/beta or duplex alloys which are harder and stronger with limited cold ductility. Lead can be added as an alloying element resulting in a brass that can be rapidly machined and produces minimal tool wear. Additions of aluminium, iron and manganese to brass improve strength, whilst silicon additions improve wear resistance. |
Key Properties |
| • High ductility (alpha alloys) • Can be hot worked • Hardness and brittleness increase with increasing beta alloy formation (i.e as zinc content increases above 37% zinc) • Aesthetically pleasing colour |
Applications |
High Pressure Gas Valves |
| High pressure gas valves are commonly made from high tensile brass containing small additions of aluminium, iron or manganese. |
Plumbing Systems |
| Dezincification resistant brass is used for fittings in valves, connectors and taps in pump and plumbing systems. This particular alloy contains a small addition of arsenic and is specially heat treated so that the composition is homogeneous as water in some countries will attack zinc rich areas of the metal. |
Marine Applications |
| Additions of tin or aluminium to either alpha or duplex brasses improves corrosion resistance in sea and brackish waters for applications such as propellers. |
Gilding Metals |
| Brass containing 10 to 20% zinc has a very similar colour to gold. Hence, this composition is often used for costume jewellery and architectural applications. |
Other Applications |
| Heat exchangers, springs, car radiators, fasteners, hot formed parts, extruded sections, forgings, condenser tubes, architectural, sections, pressure tubing, bearings, bushes, ornamental features, gearwheels. |
| Primary Author: Dr. Agnes Segal Source: Materials Information Service, “Using copper and copper alloys” edited by Justin Furness. For more information on this source please visit The Institute of Materials |