All About Brass as a CNC Manufacturing Material

Brass is a metal alloy that is antibacterial, resistant to seawater, and easy to process. The metal is primarily composed of copper and zinc, but also contains trace amounts of lead, iron, and other elements. In 2024, the United States became the world’s sixth largest brass producer, with a total production of 1.1 million tons, a year-on-year decrease of 10%. The largest is Chile (5.3 million metric tons), followed by Congo (3.3 million metric tons) and Peru (2.6 million metric tons).

What is brass

Brass is a workable, machinable, antibacterial, and anti-biofouling material. As we briefly introduced in the introduction, brass is a metal alloy of copper and zinc, usually golden yellow, but may appear red if the alloy contains a lot of copper. This type is called “red brass”. The content of copper and zinc (or other alloying elements) in brass will determine its type and characteristics. Lead in brass improves its corrosion resistance and machinability while adding iron will make it harder and easier to forge.

Due to its excellent mechanical properties, corrosion resistance, and good electrical conductivity, it is widely used in machinery manufacturing, electronic appliances, architectural decoration, musical instruments, and automotive industries.

Types of brass:

Common brass:

Composed of copper and zinc, the zinc content is between 20% and 40%. The higher the zinc content, the higher the strength, but the plasticity decreases.

260 alloy (Cartridge Brass)

Composition: 70% Cu, 30% Zn
Features: good toughness, deep drawing, good corrosion resistance
Application: bullet shells, pipes, decorative parts

280 alloy (Muntz Brass /Muntz Metal)

Composition: 60% Cu, 40% Zn
Features: high strength, seawater corrosion resistance
Application: ship accessories, marine industry, architectural decoration

Special brass:

It refers to the addition of lead (Pb), aluminum (Al), iron (Fe), silicon (Si), and other elements to a copper-zinc alloy to improve wear resistance, corrosion resistance, or strength.

C360 alloy (Free-Machining Brass)

Composition: 61.5% Cu, 35.5% Zn, 3% Pb (lead)
Features: Adding lead (Pb), extremely easy to cut, suitable for precision machining
Application: automatic lathe processing parts, bolts, nuts, electrical connectors (lead improves machinability)

385 alloy (Architectural Bronze)

Composition: 57% Cu, 40% Zn, 3% Pb
Features: Lead-containing, easy to process, strong weather resistance, suitable for architectural decoration
Application: door and window frames, handrails, architectural decoration (lead improves machinability)

464 brass (Naval Brass)

Composition: 60% Cu, 39% Zn, 1% Sn (tin)
Features: Adding tin (Sn) to improve seawater corrosion resistance
Application: ship parts, propellers, seawater pipelines (tin improves seawater corrosion resistance)

Properties of Brass

.	Alloy 260	Alloy 280	Alloy 360	Alloy 385	Alloy 464
Composition (wt %)	Cu: 68.5 – 71.5 Zn: 28.5 – 31.5 Fe <= 0.05 Pb <= 0.070	Cu: 59 – 63 Zn: 40 Fe <= 0.070 Pb <= 0.3	Cu: 60-63 Zn: 35.5 Fe <= 0.35 Pb <= 2.5-3.7	Cu: 55 – 59 Zn: 36.65-41.65 Fe <= 0.35 Pb <= 2.5-3.5	Cu: 55 – 59 Zn: 36.65 – 41.65 Zn Fe <= 0.35 Pb <= 2.5-3.5
Density (g/cm3)	8.53	8.39	8.49	8.47	8.41
Hardness, Rockwell (F, B)	54 F	85 F	78 B	65 B	55 B
Yield Strength (MPa)	75	145	124-310	138	172-455
Ultimate Tensile Strength (MPa)	300	370	338-469	414	379-607
Elongation @ Break (%)	68	45	53	30	50
Modulus of Elasticity (GPa)	110	105	97	–	100
Machinability (%)	30	40	100	90	30

Common applications of brass:

Hardware parts: nuts, screws, valves, bearings, etc.
Electronic and electrical: connectors, terminals, heat sinks, etc.
Architectural decoration: door handles, lamps, railings, etc.
Musical instruments: brass instruments such as trumpets, saxophones, trombones, etc.
Shipping industry: propellers, seawater pipes, etc. (special brass resistant to seawater corrosion

Advantages and disadvantages

Brass has many advantages. In addition to being one of the easiest materials to machine (easy-to-machine brass has a 100% machinability rating), it also has a low coefficient of friction (in layman’s terms, it has a very smooth surface, making it ideal for parts that need to slide against each other without wearing out quickly). The copper content in brass can kill certain types of bacteria, making it a go-to material for high-contact surfaces like door handles. It’s also used in the marine industry due to its biofouling properties, which means algae and barnacles won’t grow on it.

The main disadvantage of brass is that it tarnishes easily; if not properly cared for, brass can develop unsightly black stains from oxidation. To prevent this, many people apply a layer of varnish to their brass. Brass is also not hypoallergenic (thanks to the copper and zinc) and may cause some skin irritation for those with sensitive skin. Again, treating brass with a varnish can prevent this. Finally, brass is more expensive than other metals due to its high copper content (copper is notoriously expensive).

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