Brass is a combination alloy of two metals namely copper and zinc with their concentration determining the brass type. Its physical appearance is in form of a golden-yellow color although higher copper levels can give it a reddish color.
However, to enhance some particular properties of the brass alloy, we can have additional alloying elements such as lead or tin. Addition of lead to brass alloy greatly improves its resistance to corrosion while its hardness can be boosted by addition of iron.
How Brass Is Manufactured
We can manufacture brass alloy by following a few basic procedures. First, the copper and zinc ores have to be mined then processed into almost pure copper and zinc metals.
The two metals are then put in separate furnaces and heated to their corresponding melting points depending on the brass grade required.
Besides, the grade required will determine the percentage that the copper and zinc will be mixed and in the mix process, bubbles and impurities are eliminated.
The Brass alloy form required is then achieved by pouring the molten brass alloy into molds. This forms shapes of bar ingots or bars while plates and rods can be formed via extrusion through dies.
If some specific characteristics of the brass alloy are required, then other elements such as lead and aluminum can be added. This will depend on the intended purpose of your brass alloy.
Additionally, the process is finished by cooling and treating the brass alloy getting it ready for fabrication or used directly as it is. Finally, a quality and standard inspection is carried out to ensure that it meets the required market criteria.
Properties Of Brass Alloys
- Resistant to corrosion
- Antimicrobial properties
- Easily malleable and cast
- More prone to stress-cracking since it is stiffer compared to pure copper
- Very low melting point
- Not ferromagnetic and can easily be recycled by separating it from other metals
- Low friction coefficient
- Has excellent acoustic properties especially when used to manufacture musical instruments
- It has excellent conductivity properties
Advantages of Brass Alloy
Brass Alloy as a metal has a lot of upsides. Let’s have a look at some of its positive traits:
· Attractive Appearance
The physical appearance of Brass Alloy is in the form of a bright gold color making it appropriate for decorative architectural applications. It can also produce exquisite musical instruments and when properly buffed, it’s finishing looks good on furnishings.
· Easily Cast and Machined
Not only is the Brass Alloy easily machined and cast, its good wear properties enable the cost of fabrication to be reduced significantly. This facilitates the high-volume parts production of at the lowest cost achievable.
· Reduced Friction Coefficient
The Brass Alloy has a relatively low coefficient of friction. This means that you comfortably apply it in situations requiring sliding-wear motions.
· Can Be Recycled
You can collect used Brass Alloy material as scrap metal and recycle it. You can then remelt it and fabricate it into any other desired form indefinitely.
This makes brass alloy a very sustainable industrial raw material and reduces the cost of production. Additionally, you get to conserve the environment since you will no longer need additional mineral resources.
· Resistant To Corrosion
When you expose your brass alloy to air, it reacts with the oxygen forming an oxide protective layer. Some brass alloy grades are also resistant to saltwater and chemicals making them suitable for plumbing and marine applications.
· Antibacterial
The copper contained in your brass alloy has certain microbial properties that prevent bacterial growth on its surface. You can use Brass Alloy to manufacture food processing and hospital equipment that have hygiene as a basic requirement.
Limitations Of Brass Alloy
· Weight
Compared to other commercial metals, Brass alloys have a relatively higher density. This means that parts you manufacture using Brass Alloy are heavy and processing, transporting and installing them is costly.
· Easily Tarnished
Oxidation normally makes the brass alloy turn blackish if you don’t take good care of it. The solution to this is coating the brass alloy with a clear lacquer.
· Hazardous
In the process of melting the brass alloy and hot working it, there is emission of very toxic zinc oxide fumes. This means that anyone handling it needs to wear protective clothing and the room properly ventilated.
Additionally, you need to take extra environmental precautions to avoid pollution. The toxic zinc emissions have to be trapped and properly filtered.
· Non-hypoallergenic
Coming into contact with brass alloy may lead to mild skin irritations due to the presence of copper and zinc. You can counter this by treating the brass alloy with a lacquer coating.
· Non-sparking
Brass alloy has an extremely good electrical and thermal conductivity. This makes it prone to overheating and can even spark when applied in certain environmental conditions.
How Brass Alloy Vs. Bronze Compare
You can easily mistake these two metals to be the same but in reality, they are totally different. We can take a swipe on what actually differentiates them.
· Composition
While brass is majorly composed of copper and zinc, it may also contain other metals like lead and iron. Other elements may include silicon, aluminum or manganese but in very small quantities.
Bronze is basically an alloy of mainly copper and tin but may also include other elements. Among them are aluminum, manganese or traces of phosphorous and silicon.
· Color
The appearance of brass is usually golden yellow or a bright reddish gold. Bronze does not have the brightness of brass but has a reddish-brown appearance.
· Properties
Brass is easily malleable compared to its component metals but its hardness is not as steel. Besides being resistant to corrosion, its melting point is very low.
Bronze on the other hand conducts electricity and heat better than steel while being resistant to fatigue. Additionally, it is hard with the melting point being higher than that of brass alloy.
Application
Brass is mainly used in the manufacture of decorations and musical instruments. We can also use it in devices used in explosives and to make tools requiring low friction.
Bronze is used in reflectors and mirrors, making electrical connectors and springs. Sculptors can also be made using bronze in addition to making bells and ship fittings.
Strengthening Brass Alloy
We can strengthen and improve certain characteristics of brass alloys by basically adding or removing some metal elements. This means that we can alter alloy traits such as it’s resistant to corrosion or strength depending on the desired application.
Let’s have a look at some of the additional metal elements that can impact brass alloys:
i. Adding Lead to the Brass Alloy improves its malleability since it makes it soft and easy to work with. It should be noted that it should not exceed 2% due to health concerns when lead is inhaled.
ii. The addition of Tin strengthens the Brass Alloy therefore improving its durability. It also improves its heat resistance and corrosion resistance
iii. The addition of Manganese is usually for cosmetic purposes and the Brass Alloy is a deep brown color.
iv. Arsenic helps the Brass Alloy with stability in certain environments because it increases its resistance to dezincification.
v. Nickel has an aesthetic on Brass Alloy and gives it a silver color appearance.
Safety of Brass Alloy Application
Brass Alloy is absolute safe to use in very many domestic and industrial engineering applications. However, great caution should be taken especially in applications involving the food industry.
Brass Alloys are known to readily react when they come into contact with any acidic food having a PH value of less than 6. Brass is also known to affect some microscopic organisms since it can easily inhibit their growth.
Finally, if you skin is very sensitive, you should avoid any physical contact with brass alloy metals. This is because they are known to cause some form of allergic reaction upon contact.
Preventing Brass Alloy from Corroding
When the brass alloy comes into contact with air, then oxidation occurs and the process of corrosion begins. This can lead to a phenomenon called patina where the color of the brass alloy will begin to change.
You can prevent this by applying a form of sealant over the brass alloy metal surface that prevents contact with air or water. To maintain the natural appearance of the brass, it is advisable that you apply a clear coat of sealant.
In the event that the sealant wears out or has been breached, you can easily remove it then thoroughly clean the brass alloy surface. You can then apply a fresh clear coat of sealant for continued protection.
Classification of Brass Alloy by Type
Brass Alloy is available in very many types depending on the material composition. The most common types we can discuss are the Alpha, Alpha-beta and Beta types of Brass Alloy.
· Alpha Brass Alloy
The composition of this metal alloy ranges between 67-72% of copper together with 28-33% of zinc. Because they are easily malleable, they are most suitable for applications that involve forging, pressing and any other related procedures.
Their structure is such that it is face-centered with just a single phase. Since copper concentration in them is very high, they tend to have a rich golden color compared to the other types.
Its physical properties are basically almost the same as for copper meaning machining it is a bit difficult. However, it is still very strong and robust with a very high resistance to corrosion.
· Alpha-beta Brass Alloy
We can also refer to them as duplex brasses with a copper concentration of about 55-65% and 35-45% zinc concentration. They are usually hot-worked having both the alpha and beta phases in their structure.
It is the strongest among the three types having 45% zinc in it. Their physical appearance is also brighter compared to the alpha brasses.
· Beta Brass Alloy
This Brass Alloy has a 50-55% copper concentration combined with a 45-50% zinc concentration. They are the most suited for casting applications since they are very strong and hard hence can only be hot-worked.
Their physical appearance is usually brighter than the other types since their zinc content is higher than the other types. Besides, their application is mostly in situations that require high strength such as bearings, valves as well as gears.
· Gamma Brasses
The copper concentration here is at 33-39% while zinc is about 61-67%. Their physical structure is in the form of a cubic lattice with its phase being an intermetallic compound.
Their applications are usually complex and specialized. The most common is the making of electrical contacts having very high strength.
Classification of Brass Alloy by Grade
We have several grades of brass alloy each tailored to cater for various specific applications. The main way we differentiate the different grades is through their copper and zinc concentrations in addition to the other elements.
Let us have a detailed look at each of the available Brass Alloy grades:
· Alloy 200
This type of brass is also called the Alpha Brass having a very high copper concentration of about 95-99%. Because their resistance to corrosion is very good, they make very good plumbing fixtures and components.
Their electrical conductivity is very good owing to the fact that they have a high copper content. They make very good electrical and electronic components like connectors.
· Alloy 210
Sometimes known as the C21000 or the Gliding Metal, it is composed of 95% copper and 5% zinc with traces of Lead, Aluminum and Iron. It is very ductile hence you can easily cold work it.
Its physical appearance is a deep red color. It mostly applicable in situations where formability is key in forming the final product.
· Alloy 220
Popularly known as Commercial Bronze, it is made up of 90% copper and 10% zinc together Lead, Silicon and Aluminum traces. It is very strong with good corrosion resistance and highly ductile.
It is mostly used in applications that don’t require a lot of strength but need to be formidable.
· Alloy 230
This Brass Alloy is also called Red Brass having 85% copper together with 15% zinc and trace elements of Lead, Aluminum and Iron. Besides being resistant to corrosion, it is strong and ductile with excellent formidability.
· Alloy 260
The common name for this Brass Alloy is Cartridge Brass. Its metal composition is 70% copper alloyed with 30% zinc but having some impurities. It can be easily processed using cold working since its hot-formability characteristic is very good.
Its application is mainly in making ammunition, fasteners and various types of hardware.
· Alloy 272
It is commonly called Yellow Brass and has a zinc composition of about 63% Copper and 37% zinc. Its physical appearance is a yellowish-gold color.
Besides being very strong, it has a very high formidability with exceptional ductility. Its major application is mainly in the architectural, construction and industrial settings.
· Alloy 280
Also called the Muntz metal with 60% and 40% copper and zinc concentrations respectively. For additional strength, this brass alloy contains small amounts of iron in them.
It was majorly used as a replacement of copper sheeting used in making boat hulls. This is because it was cheap and deterred the growth of marine organisms on it.
· Alloy 314
Its common industrial name is Leaded Commercial Bronze having 89% copper, 9% zinc and 2% lead. It is resistant to corrosion with very good machinability making it useful in applications requiring very little machining.
· Alloy 330
The main components of this brass alloy, also called Low-leaded Brass, are 65% Copper, 34% Zinc and 1% Lead. Because of its good machinability, you can safely apply in manufacture of parts requiring easy machining and not much strength.
· Alloy 353
Commonly called the High-Leaded Brass, it is composed of 62% copper, 35.5% zinc with 2.5% lead. Other additional elements such as Aluminum, Silicon and iron are also available but in minute quantities.
It is fairly strong with very good machinability and moderately strong. Their area of application is usually those that require proper machining but with restrained strength.
· Alloy 360
We can also call it the Free Machining Brass with a composition of 60% copper and 35.5% zinc. In addition to this, it has around 3.7% of lead with little amounts of iron elements.
Its machinability is 100% therefore making it the easiest grade to process and other applications like brazing. Its industrial applications include making hardware components, valves and various types of fasteners.
· Alloy 365
This alloy grade can also be referred to as Leaded Muntz Metal and is composed of 59% copper, 39% zinc and small amounts of lead. Some of its characteristics include moderate strength with very good machinability.
It is also reasonably ductile and this makes it appropriate for use in applications that undergo thorough machining. Such applications should also have acceptable strength as a material requirement.
· Alloy 377
The industrial name for this brass alloy grade is Forging Brass comprising of 58-61% copper, 37-40% zinc and 1-2.5% lead. It also contains small amounts of silicon, iron and aluminum elements.
Some of its outstanding characteristics include both an excellent ductility and forging traits. This means that you can comfortably use hot forging on it.
· Alloy 385
Industrially known as Architectural bronze, it is made up of 59% copper and 42% zinc combined with 3.5% lead. The lead is used to improve its formability and machinability.
Its major application is in the construction industry where it is used in the extrusion of aluminum.
· Alloy 443
This brass alloy grade is commonly called the Admiralty Brass having 70% copper, 29% zinc and an additional 0.02-0.06% Arsenic.
It is very ductile and highly resistant to corrosion. Most of its fields of application are in areas that resistance to corrosion is very necessary.
· Alloy 464
The other name for this brass alloy is Naval Brass having 59% copper and 40% lead with 1% tin and lead in very small amounts. This allows the Naval Brass to have a very high resistance to corrosion besides having very good ductility.
· Alloy 485
Also called the Unleaded Naval Brass, its main components are 58.5% copper and 39% zinc. Additionally, it has other elements such as 1% zinc and 1.5% lead.
It is preferred for applications in the marine environment due to its excellent resistance to corrosion. Other considerable traits are very good ductility and an average strength.
· Alloy 770
This Brass alloy grade is composed of 55-65% copper with 18-27% zinc and an additional 10-30% nickel. It is also called Nickel Silver and has very good aesthetic visual appeal.
Besides being attractive, its resistance to corrosion and wear is impressive and is very strong. Its application is on places that do not require corrosion.
Choosing the Right Brass Alloy
When you want to settle on the best Brass Alloy grade to use in your project, you have to put into consideration the exact requirements needed. Here is a simple guide to help you with your selection process:
· Strength
You choose your brass alloy that is strong enough to sustain your project. In this light, ensure that the strength of the grade balances with the machining procedures to be carried out.
A good example for applications that undergo both forging and machining is the Alloy C377 (Forging Brass). If you require an alloy that has excellent strength and very good machinability, then the Alloy C485 (Leaded Naval Steel) is your best option.
· Machinability
You may have projects requiring very tight tolerances with extensive machining. You may settle for grades such as the Alloy C360 that has very good machinability.
This allows for precise machining while at the same achieving complex designs. This will ensure durability and also reduce wastage in the manufacturing process.
· Aesthetics
When your part has aesthetic requirements, then you should settle a brass alloy grade with a finishing that is appealing to the eyes. There is a wide variety of attractive colors ranging from a shiny yellow to a splendid golden hue.
· Formability
The formability and fabrication capabilities of the brass alloy grades is greatly influenced by the amount of zinc in the alloy. Let’s take an example of a brass alloy having a zinc content of about 33%.
It will be very easy to hot work it but extremely challenging for cold working. But if the zinc content goes above 39%, then the brass alloy grade will be very ductile and easy to cold work.
· Consider Resistance To Corrosion
If the application area of your brass alloy part is in a corrosive or harsh environment, then you should go for very high corrosion resistant grades. A very good example is the Alloy C464 Naval Brass that has superior corrosion resistance.
Applications of Brass Alloys
We can find the application of Brass Alloys in a very wide field of use such as in the manufacturing industry, technology and even in infrastructure. Let us list some of its significant applications:
· Marine Gear
Brass Alloy grades such as the Naval Brass is used in the manufacture of parts and equipment such as propellers and valves. This is because it can with stand salt water corrosion and any other electrolytic reactions that may occur at sea.
· Plumbing Industry
We commonly use Brass Alloy in the manufacture of plumbing fixtures and fittings such as pipes and water heaters among others. This is because it is highly corrosion resistant with the ability to resist the growth of bacteria.
· Architecture
When you properly buff your Brass Alloy, it can produce very excellent structural and decorative items such as statues and door knobs. Their aesthetic importance is highlighted by its natural golden color that is pleasing to the eyes.
· Bushes and Bearings
Brass Alloy has a natural lubricity that makes it suitable in the manufacture of bushes and bearings. Besides being durable enough to accommodate moderate loads, it greatly reduces the friction and any wear and tear.
· Electrical and Electronics
Brass Alloy has very conductivity properties therefore you can safely use it to manufacture electronic parts such as printed circuits boards. Other applications include shielding, making of switches, circuit breakers and plugs. Brass Alloy can also have other additional elements to boost certain characteristics. This enables you to use it in electronic applications with varied specific characteristic requirements.
· Ammunition
Bullet casings and magazine cartridges can be manufactured using a Brass Alloy grade called cartridge brass. This brass can easily be deep drawn and is resistant to high temperatures and pressure when the guns are being fired.
· Musical Instruments
Some musical instruments require precision and good castability of the material in their manufacture. Brass Alloy has these in addition to having very good acoustic properties suitable for making instruments like trumpets and saxophones.
The musical tones played in such instruments is easily produced and amplified by the brass alloy material. Additionally, the finishing and buffing of the brass alloy gives the instruments an aesthetic appeal.
Conclusion
Brass is versatile alloy with desirable mechanical, physical and mechanical properties. You can use this allow in many applications since it is easy to machine and fabricate.
For all your brass plumbing parts, D&R is your trusted partner – contact us now.
More Resources
Brass – Source: Wikipedia
Brass Alloys – Source: AZO Materials
Brass as Manufacturing Material – Source: XOMETRY
Brasses – Source: Copper