Brass is a seawater-resistant, antibacterial material. It is widely used in CNC machining since it brings forth durable parts or components. The metal is a combination of copper and zinc. In addition, iron, lead, and some other additives improve its characteristics. Brass manufacturing is preferred in many industries as it is a versatile material, highly durable, and non-corrosion.
As of 2023, the USA takes the 4th place itself as exporting brass with exports. The exports were estimated at $ 21.9 billion. Chile remained the largest exporter contributing $40 billion, Germany $29 billion and Japan $24.7 billion. These massive figures represent the global consumption of brass in machining as well as in manufacturing industries.
This guide focuses on the basics of brass, the various types of brass, and a comparison of chemical and mechanical properties. By understanding these characteristics, you will find out how brass manufacturers can fulfill the requirements of different industries effectively.
Why Brass For Machining?
Brass is an easily machined metal and antibacterial, so, it is highly valued. It is composed chiefly of copper and zinc and has a golden-yellow appearance. There are also higher copper content versions of this alloy, which will be a reddish color, known as ‘red brass’. In addition, lead is added to brass to improve the material’s ability to resist corrosion and to improve its ability to be machined precisely. The addition of iron further maximizes its hardness and also signifies its forging characteristics.
The properties stated above make manufacturing brass a preferred technique for producing components with high dimensional accuracy and precision for use in different industries such as aerospace, automotive, electronics, and medical.
Types of Brass For CNC Machining
Brass is available in many forms of alloys. Each alloy type is designed for certain uses and purposes. Here is a list of the common brass types in use today, together with their characteristics and uses.
Alloy 260 (Cartridge Brass)
Alloy 260 is a copper-zinc alloy. It has about 70% of copper, 30% of zinc, and a low percentage of impurities. It is highly valued for its high-temperature formability and cold workability. Alloy 260 is employed in applications where flexibility and strength are both desirable. Some common examples include the manufacture of ammunition casings and decorative ornaments.
Alloy 280 (Muntz Metal)
Muntz metal is typically made up of copper and zinc in almost equal measure, approximately 60% copper, and 40% zinc with some iron added for strength. In the past, it substituted copper sheeting in boat hulls to minimize barnacles and decrease costs. These are used in marine and industrial applications today because of the anti-corrosive nature of the product.
Alloy C360 (Free-Machining Brass)
Alloy C360 consists of about 60% copper, 35.5% zinc, up to 3.7% lead, and small amounts of iron. C360 is particularly noteworthy for its superior machinability; in fact, C360 possesses a 100% machinability rating. It is most suitable for the production of gears, bushings, and components that require efficient CNC machining operations.
Alloy 385(Architectural Bronze)
The particular alloy is named brass for some reason. It is composed of 59% copper, 42% zinc, and up to 3.5% lead. Its content provides improved machinability and formability that makes it ideal in architectural applications including aluminium extrusions and ornamental products.
Brass 464 (Marine Grade/Naval Brass)
The material used in marine applications has about 59% copper, 40% zinc, and 1% tin with lead as a residual. Because of its high resistance to corrosion by seawater, the material is optimally used in marine environments. However, their applications are varied and range from boat deck accessories and other maritime products meant for use in harsh conditions.
Properties of Brass
Brass properties vary across alloys, making them suitable for a wide range of industrial applications. These characteristics, including the elemental composition and mechanical properties, make the materials suitable for use in brass CNC machining and other applications. Here is a brief outline of the most observable characteristics of the popular types of brass alloy.
Key Properties of Common Brass Alloys
| Property | Alloy 260 | Alloy 280 | Alloy 360 | Alloy 385 | Alloy 464 |
| Copper (%) | 68.5–71.5 | 59–63 | 60–63 | 55–59 | 55–59 |
| Zinc (%) | 28.5–31.5 | 40 | 35.5 | 36.65–41.8 | 36.65–41.6 |
| Iron (Max %) | 0.05 | 0.07 | 0.35 | 0.35 | 0.35 |
| Lead (Max %) | 0.07 | 0.3 | 2.5–3.7 | 2.5–3.5 | 2.5–3.5 |
| Density (g/cm³) | 8.53 | 8.39 | 8.49 | 8.47 | 8.41 |
| Hardness | 54 F | 85 F | 78 B | 65 B | 55 B |
| Yield Strength (MPa) | 75 | 145 | 124–310 | 138 | 172–455 |
| Tensile Strength (MPa) | 300 | 370 | 338–469 | 414 | 379–607 |
| Elongation (%) | 68 | 45 | 53 | 30 | 50 |
| Elastic Modulus (GPa) | 110 | 105 | 97 | – | 100 |
| Machinability (%) | 30 | 40 | 100 | 90 | 30 |
Applications of Brass In Machining
Brass is widely employed across various sectors. Because, it offers easy-to-machine, corrosion resistance, and antibacterial characteristics. It can be easily formed into different products such as bullet casings, gears, precision tools or valves, pipes, and decorative fixtures. Brass is also used in marine engines, hospital instruments, and instruments. In addition, you can shape used musical gadgets both for functional and aesthetic aspects.
Advantages of Brass
Brass comes with several benefits that make it an ideal material for various applications. Some common advantages are given below;
- Machining Ease: Free-machining brass also boasts a 100% machinability rating. It makes it the easiest material to work with using CNC machining.
- Low Friction Surface: Brass is non-abrasive. Therefore, It does not rub out easily, which makes it useful especially for moving parts such as gears and bearings.
- Antibacterial Properties: The copper content is antimicrobial and eliminates bacteria – ideal for contact areas such as door handles.
- Corrosion Resistance: Brass is also resistant to acidic and marine conditions. So, it stands out in the test in harsh conditions.
- Biofouling Resistance: Brass is optimum for barnacle and algae prevention and equipment.
Disadvantages of Brass
Besides its numerous benefits, brass has a few drawbacks:
- Tarnishing: The brass products can be susceptible to staining black when exposed to air or moisture. Therefore, brass is normally painted with protective lacquers to maintain its aesthetics.
- Potential Allergic Reactions: Brass is an alloy of copper and zinc and can give an allergic reaction to the skin, especially to those with sensitive skin; however, varnish can help with this problem.
- Cost: The cost of brass is higher than other metals as it contains a high percentage of copper which is considered an expensive one.
Maximum Operating Temperature of Brass Alloys
Brass has varying temperature tolerances based on its alloy composition. The table below outlines the solidus (melting onset) and liquidus (melting completion) temperatures for commonly used brass grades:
Grades:
| Brass Grade | Solidus Melting Point (°C) | Liquidus Melting Point (°C) |
| Alloy 260 | 915 | 955 |
| Alloy 280 | 900 | 905 |
| Alloy 360 | 885 | 900 |
| Alloy 385 | 875 | 890 |
| Alloy 464 | 885 | 900 |
How Strong Is Brass?
Brass demonstrates relatively high impact resistance and wear resistance. The properties depend on the alloy composition and heat treatment. For example, cold-drawn and annealed naval brass has a tensile strength of 580 MPA which is equal to some steel grade. So, it makes it suitable for use in high-stress environments including valves and marine equipment.
Is Brass Safe to Use?
Brass is relatively harmless in engineering and structural uses. However, it has its drawbacks in situations when the probe is in direct contact with the food (the pH is below 6). Because the content of copper may be released into the food. Besides, brass can lead to skin allergies in persons with sensitive skin. The material’s antibacterial characteristics on the other hand are advantageous for parts that can be prone to coming into contact with human skin.
Is Brass a REACH or RoHS Compliant Material?
Brass alloys especially those containing lead are not intrinsically in violation of REACH or RoHS when in use. The potential health risks are normally associated with such activities as welding or machining since dust or fumes can be produced.
- REACH Compliance: As for pure brass the substance is safe as opposed to dust, vapors, or fluid. It does not pose risks of inhalation, intake, or contact.
- RoHS Compliance: Pb is permitted in brass alloys up to a weight of 4 percent under exemption 6c. Manufacturers have to declare compliance standards to meet legal requirements for the material.
Copper vs. Brass vs. Bronze
Though copper vs brass vs bronze are often grouped as “red metals,” copper, brass, and bronze have distinct properties:
- Copper: Excellent electrical conductivity makes copper popular in wiring systems and busbar applications.
- Brass: A combination of copper and zinc. Brass has low frictional characteristics and is easily machinable. It is normally used in gears and valves.
- Bronze: Since its constituent metals are copper and tin, bronze offers exceptionally high resistance to corrosion by seawater, making it suitable for marine use.
- Each metal has its specific uses; brass is the best compromise between cost, workability, and corrosion resistance.
Finishing Options for CNC Machined Brass
- Machining
- Buffing
- Electroplating
- Honing
Summary
Brass is an easily worked metal. It is often used in applications where corrosion resistance, flexibility, and low friction are crucial. These qualities make it suitable for use in almost all products ranging from musical instruments to industrial products. In addition, brass is available in many types and grades. So, it can be adjusted depending on the requirements of the application.
Prototeque- as a one-stop solution– uses brass in its products due to its dependable performance and durable characteristics. If your project demands prototype machining or mass-produced components, our faculty has in-house capability to meet your specific project needs. So, contact us today and get an instant free quote today!
