What is Brass: Typical Grade and Applications

Brass is a widely used metal alloy that has been a staple in human civilization for centuries. But what exactly is brass, and why is it so popular? Simply, brass is a versatile and valuable metal alloy made primarily of copper and zinc. Due to its excellent strength, ductility, corrosion resistance, and attractive yellow metallic appearance, brass has always been popular for everything from plumbing and musical instruments to decorative art pieces.

Today, brass continues to play an important role in modern industry. In this article, we’ll dive deep into the world of brass, exploring its composition, history, properties, types, uses, etc. Moreover, a comparison between copper, brass, and bronze will be described in this post. Read the article to learn more about brass. Let us start!

What is Brass?

Brass is an alloy of copper (Cu) and zinc (Zn) containing trace amounts of lead, iron, and other elements. The proportions of copper and zinc in brass can be altered to produce a variety of colors and mechanical, electrical, and chemical properties. However, the composition of brass is typically 66% copper and 34% zinc. Generally, brasses with a higher copper content are softer and more golden, while those with less copper and more zinc are harder and more silvery in color. Brass is known for its antibacterial and anti-biofouling characteristics. 

Brass has a brilliant gold-like appearance. Therefore, it is a popular material for drawer handles and doorknobs. Due to its low melting point, high workability, durability, and electrical and thermal conductivity, it has also been extensively utilized to create sculptures and utensils. Furthermore, the application of brass can be found in locks, hinges, gears, bearings, ammunition casings, zippers, plumbing, hose couplings, valves, and plugs and sockets. These are typical examples requiring corrosion resistance and low friction. Brass is an excellent option for musical instruments like horns and bells.

A Brief History of Brass

Brass has had a long and distinguished history, advancing many fields of human civilization for functional and aesthetic purposes. It is a material that has been fundamental in plumbing, architecture, art, music, weaponry, industry, and technology for centuries. Here is a brief history of brass:

– Humans have used brass for over 2000 years. The earliest brass dates back to the 2nd millennium BC in ancient Mesopotamia, where it was used for decorations, coins, and copper-zinc alloys produced by cementation.

– The Roman Empire expanded the use of brass between the 1st century BC and the 3rd century AD. They obtained higher purity copper and zinc, enabling stronger brass alloys. The Romans used brass for coins, utensils, art, helmets, musical instruments, and weaponry.

-Brass production declined after the fall of the Roman Empire but was revived starting in the 11th century in Europe. New furnace technologies allowed higher-quality brass production. Brass was mainly used for decorative items and some limited industrial parts.

-The Industrial Revolution led to advances in brass metallurgy and production. In 1837, James Joule discovered the Joule effect, which used brass rods in electromagnetic engines. Decorative uses of brass expanded along with plumbing, architecture, and transportation.

-In the early 1900s, hot rolling mills and extrusion presses allowed the mass production of inexpensive brass rods, sheets, and tubes. Manganese brass and aluminum brass were introduced. Brass was used for radiators, electrical parts, valves, condensers, and ammunition.

-World Wars I and II increased the demand for brass used in munitions, mechanical instruments, and chemical applications. Manganese brass, naval brass, and leaded machinable brass were widely used. Brass production accelerated to meet wartime demands.

-In modern times, concerns over lead and other toxic elements have restricted their use in brass. However, brass remains important for building construction, electronics, transportation, industrial equipment, decorative items, musical instruments, and artwork.

-The future of brass depends on continued copper and zinc mining and more sustainable production methods. Brass recycling now provides over half of all brass used today. Brass scrap is a highly valuable resource due to increasing costs and limited copper and zinc ores availability.

Composition and Properties of Brass

Brass plays an important functional and aesthetic role in the world. Brass compositions and properties are described below:

Alloying Elements

The primary components of brass are copper and zinc. The ratio of these two metals can vary, resulting in different types of brass with unique properties. The composition of brass is generally 66% copper and 34% zinc. However, by weight, brass contains between 55% to 95% copper and 5% to 45% zinc. Elements such as lead, tin, or aluminum can also be added to brass to enhance specific characteristics. Lead promotes corrosion resistance and machinability, whereas iron increases hardness and facilitates alloy forging easier. 

Material Properties 

The common types of brass grades include Alloy 260, Alloy 280, Alloy 360, Alloy 385, and Alloy 464. And we will explain them one by one later in the below part. The following table shows the material properties of these five types of brass grades.

Brass Features:

• Brass is a soft metal that may be used when a low chance of sparking is necessary.
• Brass has a bright gold look most of the time, although it may also be reddish-gold or silvery-white. A larger ratio of copper results in a rosy tone, whereas a higher percentage of zinc makes the alloy look silver.
• Brass has greater malleability than bronze or zinc.
• Brass has acoustic qualities that make it suitable for use in musical instruments.
• The metal has a low coefficient of friction.
• The melting point of the alloy is relatively low.
• It’s a good heat conductor.
• Brass is resistant to corrosion, including galvanic corrosion caused by seawater.
• Brass is a metal simple to cast.
• Brass is not a ferromagnetic metal. This renders it easier to separate from other metals for recycling.

How is Brass Made?

Brass is produced through the following basic steps:

Step 1. Mining and processing copper ore into copper metal which is almost 100%, pure copper. Zinc ore is also processed into nearly pure zinc metal.

Step 2. The purified copper and zinc metals are heated to melting points of 1083°C and 419°C in a furnace according to the desired brass composition.

Step 3. The molten metals are mixed thoroughly to form brass according to predetermined percentages of copper and zinc. Impurities and bubbles are removed.

Step 4. The molten brass is poured into molds to cast it into bars, ingots, or other shapes; or extruded through dies to form tubes, rods, or plates. 

Step 5. The cast or extruded brass is often treated using techniques like annealing, cold working, grinding, or polishing to improve properties, strength, hardness, surface finish, machinability, or corrosion resistance.

Step 6. Additives like lead, tin, aluminum, or manganese are sometimes included in the composition to produce brass alloys with specific properties depending on the intended application.

Step 7. Once cooled and treated, the brass product is finished and ready to be fabricated or used for its intended purpose. Final inspections verify that it meets the required standards.

Types of Brass

Material of brass can be divided into many types. Here we will introduce some commonly seen types: Alpha brasses, Alpha-beta brasses, Beta brasses, and Gamma brasses.

Alpha Brasses

Alpha brasses Contain 67-72% copper and 28-33% zinc. They are malleable and utilized in pressing, forging, and other related applications. In addition, they can be worked cold. Alpha brasses only have one phase and a face-centered cubic crystal structure. These brasses have a richer golden tone than others due to their high copper content. The alpha phase refers to a substitution solid solution of zinc in copper. It has properties similar to copper and is robust, strong, and relatively difficult to machine. The best formability is achieved at 32% zinc. Corrosion-resistant red brasses with a 15% or less zinc content belong here.

Alpha-beta Brasses

Alpha-beta brasses contain 55–65% copper and 35–45% zinc. These brasses, also known as duplex brasses, are suitable for hot working. They include both α and β’ phases. The β’-phase is ordered body-centered cubic, with zinc atoms in the centers of cubes, and is tougher and stronger than α. Typically, alpha-beta brasses are worked hot. Because of the higher zinc content, these brasses are brighter than alpha brasses. At 45% zinc, the alloy possesses its highest strength.

Beta Brasses

Beta Brasses contain 50–55% copper and 45–50% zinc. These brasses can only be worked hot. They are harder, stronger, and appropriate for casting. Because of the high zinc-low copper content, they are among the brightest and least golden of the typical brasses. Beta brasses are often used for higher–strength applications, such as valves, gears, and bearings.

Gamma Brasses

Gamma brasses contain 33–39% copper and 61–67% zinc. There are also Ag-Zn and Au-Zn gamma brasses, with Ag 30-50% and Au 41%, respectively. The gamma phase is an intermetallic compound with a cubic lattice structure, Cu5Zn8. Gamma brasses are typically used for specialized applications, including high-strength electrical contacts and fasteners.

Typical Grade of Brass

There are several different brass alloys. They differ little according to the elemental composition, though. Some commonly employed brass alloys in rapid prototyping are listed below:

Alloy 260 (Cartridge Brass) 

Alloy 260 is also referred to as cartridge brass. This brass alloy comprises around 70% copper and 30% zinc, with impurities. Alloy 260 has good hot formability and can be cold-worked easily. It is used in autos, ammunition, hardware, and fasteners, among other things.

Alloy 280 (Muntz Metal)

Alloy 280 contains around 60% copper, 40% zinc, and a trace amount of iron. Muntz metal was commonly used as an affordable alternative for the copper sheeting formerly placed on boat hulls to avoid the formation of marine organisms like barnacles on the hulls. 

Alloy 360 (Free Machining Brass)

Alloy 360 comprises around 60% copper, 35.5% zinc, up to 3.7% lead, and trace amounts of iron. This type of alloy is one of the easiest materials to process out of all the brasses, with a 100% machinability grade. Alloy 360 is also an excellent choice for brazing and soldering applications. Designers and machinists use this alloy to create fittings, fasteners, valves, and hardware components.

Alloy 385 (Architectural Bronze)

Alloy 385 is an alloy of around 59% copper, 42% zinc, and up to 3.5% lead. This enhances its machinability and formability significantly. Because this alloy is easy to form, it is a good architectural material for aluminum extrusions. 

Alloy 464 (Naval Brass)

Alloy 464 is also known as naval brass. This brass alloy comprises roughly 59% copper, 40% zinc, and 1% tin, with a trace of lead. The result is a metal with high corrosion resistance. It can also endure a broad range of temperature changes. Its adaptability for cold and hot forming operations, bending, soldering, and welding, among other things, makes it ideal for various applications. Applications include the different fittings used on a deck of a boat.

What are the Advantages and Disadvantages of Brass?

Brass boasts a range of benefits that make it a popular choice for various applications. Here is an overview of the advantages and disadvantages of brass:

Advantages of Brass

High Corrosion Resistance: Brass forms a protective oxide layer when exposed to air that prevents further corrosion. Some brasses resist saltwater and industrial pollutants. This property enables uses in plumbing, architecture, electronic parts, and marine equipment.

Low Coefficient of Friction: Brass has a low coefficient of friction. As a result, it is perfect for sliding-wear applications. 

Good Castability and Machinability: Brass can be easily cast, stamped, machined, and polished. It has good wear properties in cutting tools, reducing fabrication costs and difficulties. This advantage allows the economical high-volume production of brass parts, components, and objects. 

Attractive Appearance: Brass has a bright gold metallic appearance for decorative architectural elements, artistic works, musical instruments, and consumer goods. When buffed and lacquered, brass provides an attractive, durable finish for furnishings and equipment.  

Antibacterial: Brass alloys contain copper with natural antimicrobial properties. Brass surfaces inhibit the growth of germs, algae, and bacteria. This advantage makes brass suitable and safe for plumbing systems, food processing equipment, hospitals, and other areas where hygiene is important.

Recyclable: Brass scrap metal is highly recyclable and a valuable commodity. Most brass can be remelted and reformed indefinitely. This property contributes to the sustainability and economics of brass as an industrial material. Recycling helps reduce costs and the need for new mineral resources. 

Disadvantages of Brass

Relatively Expensive: Although recyclable, copper and zinc components of brass alloys cost them more than base metals like iron or aluminum and some plastics. Material and production costs can be high depending on the price of copper and zinc. This disadvantage may limit very large-scale applications of brass.  

Heavy: The density of brass alloys is higher than most commercial metals. This results in heavy parts which require more labor and resources to machine, transport, and install. The weight factor must be considered, especially in large brass assemblies and constructions. 

Prone to Tarnishing: If not properly cared for, brass can develop a blackish tarnish due to oxidation. To avoid this, brass may need to be coated with a clear lacquer.

Non-Hypoallergenic: Due to its copper or zinc content, brass can cause skin irritation in individuals with sensitive skin if not correctly treated with a lacquer coating. 

Hazardous Zinc Oxide Fumes: Melting and hot working brass at high temperatures can produce hazardous zinc oxide fumes, which require ventilation and respiratory protection for workers. Additional environmental controls may also be needed to trap and filter zinc emissions and prevent pollution.  

Non-sparking: Brass cannot be used where sparking could ignite flammable vapors or materials. The high thermal and electrical conductivity of brass poses risks of overheating and sparking/arcing in certain working environments. Intrinsically safe alloys must be used for these applications. 

Applications of Brass

Brass is essential in society, industry, technology, infrastructure, art, and culture. Here are some of the typical applications of brass:

Plumbing Fixtures and Fittings

Brass is commonly used for plumbing parts like pipes, valves, pumps, water heaters, faucets, and joints. It resists corrosion, is durable, and inhibits bacterial growth.

Architecture

Brass has decorative and structural uses in buildings. Decorative uses include door knobs, handrails, statues, artwork, furniture trim, staircases, and kick plates. Structural uses include lanterns, door hardware, roofing, and flashing. The golden color highlights architectural features.

Electronics and Telecommunications

Brass is used for electronic parts that require conductivity and corrosion resistance, like plugs, jacks, switches, condensers, printed circuit boards, and shielding. The ability to alloy brass provides specific properties for electronic applications.

Transportation Equipment

Brass is used throughout transportation for corrosion-resistant, attractive parts. Uses include door handles, trim, radiator parts, fasteners, instruments, and hardware in automobiles, trains, and aircraft. Naval brass withstands saltwater for marine propellers, pumps, and valves.

Ammunition and Cartridges 

Cartridge brass, an alloy suited for deep drawing, makes cartridges and bullet casings. The brass must withstand high pressures, temperatures, and physical stresses from firing and loading ammunition.     

Musical Instruments

The acoustic properties of brass alloys and their castability into precision bells and tubes have made them suitable for crafting musical instruments like trumpets, trombones, tubas, French horns, saxophones, bugles, etc. The brass parts help produce and amplify musical tones.

Bearings and Bushings

Brasses are suited for bearings and bushings that require corrosion resistance, durability, and moderate loads. The natural lubricity of brass also helps reduce friction and wear. Examples are phosphor bronze and tin bronze.

Decorative Objects

Brass is used for decorative items where appearance and shine are most important. Examples include statues, candlesticks, vases, lamps, chandeliers, door knockers, paperweights, and other metal art. Casting allows sharp detail and intricate shapes. The gold color is traditionally associated with prestige and style.

Marine Equipment

Naval brass and other brasses resistant to saltwater corrosion are used for propellers, pumps, valves, condensers, fasteners, and hardware on seagoing vessels and equipment. They must withstand corrosion, impacts, erosion, and electrolytic reactions in ocean environments. 

Comparison between Copper, Brass, and Bronze

All three are known colloquially as “red metals.” Copper is a nonferrous metal that exists in its pure state. Unlike bronze and brass, this metal occurs naturally and may be processed directly and immediately. 

Brass and bronze belong to the alloy. Copper is the primary element of both brass and bronze. The main secondary element of brass is zinc. It often contains lead and may include manganese, iron, aluminum, silicon, and other elements. However, bronze contains tin as its main secondary element. In addition, it also has nickel, aluminum, phosphorus, zinc, and others. 

Bronze is very resistant to corrosion caused by saltwater, but brass has great low-friction properties. In contrast, the high conductivity of copper makes it ideal for electrical applications.

The following table further summarizes other brass, bronze, and copper differences. 

Summary

Brass is an alloy of copper and zinc that has a golden-yellow color. Brass is resistant to seawater corrosion and is simple to machine and shape. Its biocidal effect makes it a good material for antibacterial applications. In addition, brass can be found in applications that need low friction. Fittings, tools, appliance parts, and ammunition components are examples of such uses. 

When you’re unsure whether brass or another material is right for your project, let LEADRP help. Our professional technicians and machinists will choose the best material for you. We also offer prototyping services such as sheet metal fabrication, CNC machining, injection molding, and 3D printing. Contact us and request a free quote today!

References

Brass – From Wikipedia

What Is Brass? Composition and Properties – From ThoughtCo