The Composition Of Brass Material:Why It’s Not 100% Copper

One of the first metals discovered by humans—purple-red pure copper—was very ductile but too soft. It was easily deformed when shaped into tools, and weapons quickly became blunt.Until some unknown ancient metallurgist accidentally smelted another mineral (smithsonite) with copper, and created a harder, more gold-colored, and more practical material: brass. This was not just an “adulteration”, but a revolution in materials.

In this article, we will discuss the reasons why we employ brass alloy instead of 100% pure copper, and how by minutely altering the composition, it serves a complete array of applications, from precision gears to intricately ornamented musical instruments. This useful guide is an evident reference to your metal casting projects, where you can understand brass material and choose the right material effortlessly.

Key Answer Summary

Which Brass Is Appropriate For Your Project? Based On More Than a Decade Of JS Precision’s Experience In Material Selection

The majority of customers are perplexed with what brass to choose in the start of a metal casting project. JS Precision, with over a decade of experience within the industry, can provide a direct answer to this query.

We have been deeply involved in the field of custom metal casting manufacturing for many years, and we have worked with a range of metal casting parts, from intricate electronic connectors to 6-meter-diameter marine propellers, and specialty use such as automobile transmission gears and medical device connectors.

We develop customized material selection solutions to satisfy various industries’ demands and have over 5,000 customers. We are intimately familiar with the composition, properties, and processing compatibility of over 30 brass grades—for example, we know that naval brass can withstand over 15 years of seawater corrosion, and we know the optimal cutting speed parameters for free-cutting brass.

This guidebook is a compendium of our project experience. Everything we recommend has been tried in the field, so you don’t waste your time on material selection mistakes and can sidestep pitfalls in your metal cast projects. You can depend on it.

JS Precision has had solutions for brass materials selection for different industries. Our custom metal casting manufacturing service is quick in responding to your order so that projects can proceed instantly after consulting, providing guaranteed assistance for your metal casting projects.

Brass’ “Formula”: Key Components And Their Mission

And now that we’ve gained an understanding of the importance of material selection, let’s break down the brass “formula.” Its main ingredient isn’t just copper, there are other key ingredients that, in combination, determine the properties of brass and make it more suitable to metal casting than copper.

The basic formula for brass is “copper + zinc,” but that’s merely the starting point.

• Protagonist One: Copper (Cu) – Lays the Foundation. Copper provides brass with its foundational electrical conductivity, heat conductivity, and corrosion resistance and is therefore the basis for brass’s functionality.
• Protagonist Two: Zinc (Zn) – Transforms Stone into Gold. Zinc is an extremely significant variable in determining brass’s properties. Dissolving in copper to form a solid solution, it substantially improves the strength and hardness of the alloy. When the zinc content increases from 0% to 45%, the color of brass will change from red to gold and then to light yellow. Furthermore, zinc is less expensive than copper (approximately $4/pound for copper and $1.5/pound for zinc), significantly reducing material expenses.

In addition to copper and zinc, brass also contains a third element as a “special guest” to offer special characteristics, as indicated in the table below:

JS Precision has extensive experience in brass material composition design and can precisely adjust the element ratios based on your project requirements to ensure the finished product meets performance standards. Please consider our custom services.

A Wise Choice: Why Is Pure Copper Less Effective Than Brass?

Since brass is copper-based, why isn’t straight copper used in engineering application? It is due to the fact that brass gets over a number of its drawbacks. The following table clearly illustrates the difference between them:

As can be seen from the table, while pure copper is a good conductor of electricity as well as heat, it is brittle, difficult to process, and expensive, and thus not suitable for most metal casting parts. Brass, however, compensates for all these disadvantages to become an ideal material in the world of engineering.

If you require high-strength, easy-processing metal casting parts, JS Precision’s custom metal casting manufacturing service will find the most suitable brass for you and help you save costs while maintaining quality.

Brass Family Tree: From The Ordinary To The Extraordinary Alloys

Brass family is not singular.Chemically, it is divided into two broad groups: special brass and common brass. Their characteristics and uses are quite varied, and the use of the right type is crucial to the success of a project.

Common Brass (Copper-Zinc Binary Alloy)

Common brass consists of pure copper and zinc and is typically designated by percentage zinc. Two normal types exist:

• CuZn37 brass: Having approximately 30% zinc, it is highly plastic and can be used for hot pressing as well as cold working. It is extensively applied to make pipe fittings, radiators, etc.
• CuZn40 brass: Having the maximum application with a balance of strength and plasticity, it is employed to make valves, connectors, ornaments, etc.

Special Brass (Multi-element Alloys)

Special brass provides a third component to copper and zinc for conferring special characteristics. Some of the typical forms are:

• Naval Brass (Cu-Zn-Sn): Tin addition provides it with excellent resistance to seawater corrosion and is applied to marine propellers and valves.
• Free-cutting brass (Cu-Zn-Pb): With the inclusion of lead, it possesses good cutting properties and is applied to precision screws and nuts.
• Silicon brass (Cu-Zn-Si): With the addition of silicon, it exhibits excellent casting fluidity and good wear resistance, making it a good choice for complex castings (such as gears and pump cases).

The different brass materials meet different requirements, and choosing the right one brings out the best value in your parts.

Ways To Easily Identify And Select Copper, Brass, And Bronze

In real projects, the majority of people confuse pure copper, brass, and bronze because of the incorrect selection of material. But if you know about some characteristics, it is easy to tell them apart. The minute details are in the table below:

For example, pure copper is the appropriate material for conductive components, whereas components utilized in naval applications need brass (naval brass) or bronze. By identifying these properties, you can simply avoid material errors.

Casting Vs. Forging: The Chemical Secrets Of Two Manufacturing Processes

After selecting a kind of brass, you also need to select a manufacturing process. Two common brass processing methods are casting and forging. The requirements for the brass composition of each of them are completely different, having an immediate impact on the quality of the finished product. This is extremely critical in metal casting work.

Casting Brass

Brass is cast by pouring molten brass into a mold. The design intent is to enable the molten metal to possess good fluidity in order to fill very complicated molds fully with minimal shrinkage in the casting.

Compositional Characteristics: Silicon (Si) is added normally in order to raise fluidity, and grain refiners like manganese (Mn) and others are added as additives. Lead content requirement is lower than that of the forged brass, and some of the cast brasses contain a slightly higher proportion of lead.

Forged Brass (Processed Brass)

Forged brass is created by mechanical methods such as rolling, extrusion, and drawing. Its design aim is to add high plastic deformation (ductility) to the brass to facilitate easy processing subsequently.

Compositional Features: The zinc is usually lower than 37% in such a manner that the brass does not become susceptible to cracking under hot and cold working. When the forging is to be machined, lead (Pb) is added intentionally for improved machinability.

Briefly, casting is suitable for parts with complex geometries, while forging is suitable for parts that require high ductility and strength.

Industrial Case Study: Casting a Large Marine Propeller – The Art Of Melting And Casting Brass Alloys

We have covered a great deal of theoretical material up to now. Let us now study a real-world case study – a metal casting project in which JS Precision produced a large marine propeller for a shipyard to demonstrate how brass alloys can provide practical solutions to real problems.

Project Background

A propeller of large size, 6 meters in diameter, of a 10,000-ton class cargo ship had to be cast by a shipyard. The propeller would operate in extremely corrosive seawater for an extended period of time and endure huge torque and impact. This required ultra-high strength properties of the material, corrosion resistance (especially to cavitation resistance), and integrity of the casting.

Core Challenges

• Dimension and Integrity: As the casting was of enormous size, how could the molten metal pour into the complete mold without any gaps?
• Mechanical Properties: How could the propeller blades possess sufficient strength, toughness, and hardness to resist the gigantic resistance of seawater?
• Corrosion Resistance: Regular brass is susceptible to dezincification corrosion and cavitation corrosion at blade tips under high-speed running, leading to material failure.

JS Precision’s Solution

1.Material Choice:

Special aluminum bronze/manganese brass(“brass” is used in a general term here,the alloy is based on copper and is predominantly made of aluminum, manganese, and iron and is most commonly classified as part of the family of brasses).

2.Composition Design:

Aluminum (Al) is a major constituent, forming a close aluminum oxide protective coating on the surface that provides excellent seawater corrosion and cavitation erosion resistance while greatly improving the strength and hardness of the alloy.

Manganese (Mn) further improves the alloy’s strength and toughness, especially impact toughness, which is crucial for wave impact resistance. Iron (Fe) enhances grain size, which enhances strength and hardness, as well as cavitation resistance.

3.Cast Process:

Computer simulation software (e.g., Magma and ProCAST) is utilized before casting to predict and optimize the pouring, solidification sequence, and potential shrinkage cavities. A high-tech riser and chill system is employed to ensure that the whole propeller solidifies in a uniform, sequential manner from blade to hub. Castings undergo rigorous UT (ultrasonic) and RT (X-ray) to ensure internal quality to the utmost level of class societies (such as DNV and ABS).

Achievements and Value

The corrosion and mechanical properties of the casted propeller are far above normal requirements, which means its service life is over 50% greater compared to conventional brass propellers. It enables the integrated molding of these heavy and complex structural components, which cannot be achieved by other fabrication processes such as welding process.

This provides customers with safe, long-lasting, and trustworthy critical ship components for efficient and safe shipping. The overall metal casting price is $8,000 less than conventional solutions.

JS Precision’s online metal casting services efficiently address the issue of casting large, complex metal casting parts. We strictly control metal casting prices to provide you with economical services. You are welcome to contact us for inquiries.

How To Choose The Right Brass For Your Project?

After you read this case study, you may wonder, “How do I choose the right brass for my project?” In fact, by walking through four steps, you will be able to choose the correct brass material and make no mistakes.

1.Consider the application environment: If the component needs to be used in a seawater environment, choose naval brass. If the component needs excellent conductivity, choose high-copper brass (e.g., brass with over 90% copper content).

2.Consider the processing method: If the component needs extensive turning and milling, choose leaded free-cutting brass. If the component will require delicate casting, choose cast silicon-brass.

3.Match cost with performance: When meeting a necessary requirement, choose the most economical grade. To illustrate, for run-of-the-mill decorative pieces, use 64 brass instead of expensive specialty brass. This assists in effectively managing metal casting expenses.

4.Seek an expert: If you are not sure of your material choice, forward your specifications to a materials supplier or a fabrication service provider like JS Precision for professional guidance to avoid losses on your project from inadvisable material selection.

JS Precision will recommend the appropriate brass material based on your project details. Our one-to-one metal casting parts service is tailored to your specific requirements, making ordering simple and straightforward, from order request communication to delivery of products.Welcome to choose us.

FAQs

Q1: Does brass rust?

Brass is not as prone to rust as iron, producing a reddish-brown rust. However, it does oxidize, and a thick, dark oxide layer develops on its surface. This layer is commonly known as “patina.” This layer protects the metal underneath from further corrosion. However, under certain conditions, such as prolonged exposure to hard water, brass acquires a green basic copper carbonate, known by the common name “verdigris.”

Q2: What is lead-free brass?

Because of environmental and health factors, especially in those parts which are directly exposed to the human body, such as pipes for drinking water, the industry developed “lead-free brass.” This type of brass replaces the lead composition in the traditional brass with compounds such as bismuth and silicon. Although it does not contain any lead composition, its machinability is similar to that of lead-containing brass, fulfilling most of the machining requirements without suffering the human body’s health-degrading influence of lead.

Q3: Why are brass castings occasionally subjected to heat treatment?

Brass castings are occasionally heat treated. Most common heat treatment process is annealing, and the treatment is done for two general reasons. First, it is to eliminate internal stress developed during the process of solidification so that deformation or cracking while in use thereafter is prevented. The second is to homogenize the internal structure of the casting to encourage more uniform performance by all portions, thereby overall quality.

Q4: Is brass magnetic? How do I easily differentiate brass from regular steel?

Basic copper-zinc brass is not magnetic. No matter how you use a magnet to pull a brass piece, it will not be pulled. However, most basic steel is magnetic, and magnets pull steel like a magnet. So, to simply sort brass from basic steel, simply use a magnet to test it. If it’s pulled, it’s basic steel, otherwise, it’s most likely brass.

Summary

Brass is a smart combination of copper, zinc, and other minerals. Each one adds up to some characteristics, and each brass type is suited to being used in specific situations. From basic faucets to massive ship propellers, brass’ composition advantages place it as a metal casting material that can do it all. Choosing the right brass will make your project stronger, cheaper, and more efficient.

JS Precision has a deep accumulation in the manufacturing of metal casting parts and the provision of online metal casting services. Our metal casting prices are clear and affordable, with an easy ordering process, offering complete support for your project.

No matter if your project entails accuracy machined mechanical parts or large castings requiring injection casting, our extensive brass material expertise can help you. Contact our material experts immediately to receive free material selection and process advice for your next project!

Disclaimer

The content of this website is for reference only. JS Precision Services expressly disclaims any representations or warranties, express or implied, as to the accuracy, completeness or validity of the information provided. Any performance parameters, geometric tolerances, design features, material specifications or processes mentioned should not be considered as any commitment or guarantee by JS Precision for products offered by third-party suppliers or manufacturers on its network or other channels. Buyers seeking quotes for parts are responsible for confirming their specific needs and product suitability. If you have any questions or need further information, please contact JS Precision directly.

JS Precision Team

JS Precision is an industry-leading company, focus on custom manufacturing solutions. We have over 20 years of experience with over 5,000 customers, and we focus on high precision CNC machining,Sheet metal manufacturing,3D printing,Injection molding,Metal stamping,and other one-stop manufacturing services.
Our factory is equipped with over 100 state-of-the-art 5-axis machining centers, ISO 9001:2015 certified. We provide fast, efficient and high-quality manufacturing solutions to customers in more than 150 countries around the world. Whether it is small volume production or large-scale customization, we can meet your needs with the fastest delivery within 24 hours. Choose JS Precision this means selection efficiency, quality and professionalism.
To learn more, visit our website:jsmachining.com

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