Bronze is an alloy consisting primarily of copper, with about 12% tin and often with the addition of other metals (such as aluminum, manganese, nickel or zinc). These additions produce a range of alloys that may be harder than copper alone, or have other useful properties, such as stiffness, ductility, or machinability.
Custom bronze parts are typically constructed from very ductile alloys. By way of comparison, most bronzes are considerably less brittle than cast iron. Typically bronze only oxidizes superficially; once a copper oxide (eventually becoming copper carbonate) layer is formed, the underlying metal is protected from further corrosion. Further bronze properties include melting points that vary depending on the ratio of the alloy components and is about 950 °C (1,742 °F). Bronze is usually nonmagnetic, but certain alloys containing iron or nickel may have magnetic properties.
Copper and its alloys have a huge variety of uses that reflect their versatile physical, mechanical, and chemical properties. Some common examples are the high electrical conductivity of pure copper, low-friction properties of bearing bronze (bronze which has a high lead content— 6–8%), resonant qualities of bell bronze (20% tin, 80% copper), and resistance to corrosion by seawater of several bronze alloys.
Bronze EDM Advantages
There are many benefits of using custom bronze parts. One of the primary benefits is that high precision bronze parts is that they are much harder than standard copper. Bronze machining also creates parts that are highly corrosion resistant. Through the formation of a protective surface film, most copper alloys resist many corrosive environments. Other advantageous bronze properties, include:
- Elevated temperature resistance
- High friction & wear resistance
- Good machinability
- Can be brazed & soldered
One of the main disadvantages of bronze EDM that should be considered is that it is a softer metal that is weaker and more expensive than steel. However, there are many applications that demand bronze over any other type of metal.
There are three main alloy categories that contain bronze properties. They include the following.
This alloy typically has a tin content ranging from 0.5% to 1.0%, and a phosphorous range of 0.01% to 0.35%. These alloys are notable for their toughness, strength, low coefficient of friction, high fatigue resistance, and fine grain. The tin content increases the corrosion resistance and tensile strength, while the phosphorous content increases the wear resistance and stiffness. Common applications, include:
- Electrical products
- Corrosion resistant equipment
This bronze EDM alloy has an aluminum content range of 6% – 12%, an iron content of 6% (max), and a nickel content of 6% (max). These combined additives provide increased strength, combined with excellent resistance to corrosion and wear. Some of the applications, include:
- Marine hardware
- Sleeve bearings
- Corrosive fluid pumps & valves
This is an alloy that can cover both brass and bronze (red silicon brasses and red silicon bronzes). They typically contain 20% zinc and 6% silicon. Red brass has high strength and corrosion resistance and is commonly used for valve stems. Common applications, include:
- Pump components
- Valve components