What Is Free Cutting Brass?
Free cutting brass is a highly machinable material made from a brass alloy consisting mainly of copper and zinc, mixed with additives such as lead and phosphorus.
Free cutting brass is easy to cut and suitable for machining, and it produces a beautiful finish with little discoloration or deformation due to heat or friction during cutting. Free cutting brass is used for automotive parts, architectural hardware, and electric appliance parts. It is also widely used for ornaments and musical instruments.
Uses of Free-Cutting Brass
The main applications of free cutting brass are as follows:
1. Automobile Parts
Engine parts, brake parts, and fuel injectors are examples. Examples of automotive engine parts include injector connectors and cylinder head gaskets.
Injector connectors are part of the fuel injector system and are used to inject fuel into the cylinder. Cylinder head gaskets are parts that adhere to the cylinder head to the cylinder block and must withstand high temperatures and pressures.
2. Electrical and Electronic Equipment
Connectors, terminals, and switches are examples.
3. Construction Parts
Handles, doorknobs, and locks are examples.
4 . Parts for Food Processing Machinery
Mixers, shredders, cutters, etc.
5. Aircraft Parts
Engine parts and lightweight structural parts are examples. Examples of aircraft engine parts include fuel injectors and turbochargers.
Fuel injectors are used to feed fuel into the engine. A turbocharger is a part used to feed air into the engine and may include a blow-off valve made of brass. A blow-off valve is a valve used to vent excess boost pressure (pressure delivered to the engine by a turbocharger, for example) that occurs during engine operation.
Properties of Free Cutting Brass
1. Cutting Performance
Free cutting brass is the material with the highest cutting performance among copper alloys. This is because its moderate hardness allows the cutting edge to bite easily into the material and efficiently transmit cutting force. It also has high abrasion resistance, which minimizes the deterioration of the cutting edge due to friction generated during cutting, and maintains cutting performance. In addition, the low thermal transformation during cutting prevents excessive heating of the workpiece and cutting edge, resulting in beautifully finished workpieces.
2. Machinability
Machinability is an indicator of how easily a material is to machine. Free cutting brass is suitable for machining because of its moderate hardness and flexibility. Especially in cutting, the cutting edge can easily bite into free cutting brass and efficiently transmit cutting force. Free cutting brass is also relatively soft, making bending and drilling easy.
After machining, cutting chips and burrs on the surface can be easily removed, resulting in an extremely smooth and beautiful surface finish.
3. Corrosion Resistance
Free cutting brass is a material with excellent corrosion resistance and is highly resistant to corrosion. The reason for the high corrosion resistance of free cutting brass is due to the properties of copper.
Copper is a corrosion-resistant material under normal conditions because it forms an oxide film on its surface. The oxide film is formed when copper reacts with oxygen in the air and protects the surface. Copper is also self-healing, so when the oxide film cracks, the copper re-oxidizes and covers the surface, again protecting it.
Free cutting brass is a brass alloy of copper and zinc, which also forms an oxide film. Therefore, free cutting brass has the characteristics of both copper and zinc, and is a material with excellent corrosion resistance.
4. Electrical Conductivity
Copper is an excellent conductor of electricity, and free cutting brass is often used in electrical components and circuits because of its conductive properties.
5. Abrasion Resistance
Free cutting brass is a material that is extremely resistant to abrasion. The reason is that free cutting brass has high hardness and strength and a smooth surface. It is made by mixing a brass alloy consisting mainly of copper and zinc with additives such as lead and phosphorus, which gives it high hardness and strength and excellent abrasion resistance.
One of the reasons free cutting brass is resistant to abrasion is its smooth surface. A smooth surface reduces the contact area, which in turn reduces wear. Free cutting brass is also a material with high self-lubricating properties, which reduces wear without the use of lubricants.
6. Weldability
Free cutting brass has excellent weldability because of the properties of copper. Copper softens when heated, making it suitable for welding. In addition, free cutting brass has additives such as lead and phosphorus that reduce oxides formed during welding, preventing oxidation of the weld surface and making stronger joints possible.
7. Heatability
Free cutting brass can be heated to modify its shape after cold working.
8. Thermal Conductivity
Because free cutting brass has excellent thermal conductivity, heat is evenly transferred from the heated area and cooled quickly, resulting in less deformation and distortion.
9. Beautiful Color
Free cutting brass is used for ornaments and interior goods because of its beautiful yellow hue and luxurious appearance.
10. Rust Resistance
Free cutting brass is resistant to rust due to the characteristics of copper. Copper oxidizes by reacting with oxygen in the air, and when an oxide is formed, its surface is covered with the oxide to prevent the next oxidation, thus making it rust-resistant. The oxide is also a substance called copper oxide, which is usually greenish-blue, and this may give copper its characteristic green hue.
Lead and phosphorus in free cutting brass are elements used to improve the workability and machinability of free cutting brass. However, lead and phosphorus also have the effect of providing rust resistance. Furthermore, free cutting brass is resistant to salt and acidic substances, making it suitable for outdoor use, as it is resistant to rust even in humid environments.
Other Information on Free Cutting Brass
1. Forging Process
Free cutting brass is also suitable for forging, which increases the durability and strength of free cutting brass.
2. Heat Treatment
The hardness and strength of free cutting brass can be changed by heat treatment, so the workability and durability of free cutting brass can be improved by heat treatment.